Overdoing It

by dirty little secret

Rating: mature
Tags: Sex, Twilight Sparkle, Princess Celestia, My Little Pony: Friendship is Magic, Romance, Princess Luna, Porn, Fetish
Length: 13048

Twilight is ready to start a family of her own, and she can't think of anyone she'd rather have helping her with that than Celestia and Luna. A few potions is all it will take. But then the two sisters get a little carried away with things...

Twilight is ready to start a family of her own, and she can't think of anyone she'd rather have helping her with that than Celestia and Luna. A few choice potions is all it will take. But then the two sisters get a little carried away with things ... and, well, they end up overdoing it.

Contains: futa on female, futa on futa, potion-enhanced fertility, big balls, excessive cum, cum inflation, sloppy seconds, pony in lingerie/panties, threesome, impregnation, incest.
An entry into the Incest is Wincest Contest.
Cover image by SilFoe.

Published 2020-01-17 19:40:02 UTC
Last updated 2020-01-17 19:40:02 UTC

Luna and Celestia

Twilight Sparkle trotted briskly down the hallway high up in Canterlot Castle's Tower of the Sun. She held her checklist hovering in the air in front of her as she went, going over everything she'd so carefully packed in her saddlebags. Everything had already been triple-checked, of course ... but one more run through the checklist wouldn't hurt, would it?

She levitated each item out and visually verified it as she went through the list, making absolutely sure of every single thing. Fertility potion, female. One bottle. Fertility potion, male. Two bottles. Futa potion, temporary. Two bottles. Pregnancy testing crystal. One, two, three. Two backups, just in case. Lingerie ... well, she wasn't about to pull that out of her saddlebag as she went down a public hallway. The itemization down that side of her checklist would have to wait.

It would have had to wait anyway. She was almost there, almost to Celestia's private bedchambers. She'd been here so many times before ... but never for a purpose like what she intended for this evening. In her mind, it was the warmest, most nourishing place she could think of, which meant it was the perfect place for her to start her new family. And so what if she didn't have the right stallion yet? What if there was no 'right stallion' for her? It wasn't necessary. Not with modern potionry to the rescue!

Just as she came up to the big, sun-emblazoned door, Luna came around the bend from the other direction ... no doubt after crossing the high bridge between the two main towers. Twilight stopped just shy of knocking on Celestia's door, instead waiting for Luna to accompany her inside.

And Luna – in her usual way – made no rush of things. She slowly and calmly closed the distance, and she didn't speak until she could do so at a volume just above a whisper. “Are you certain you want to do this, Twilight?”

Twilight paused for a moment, in all honestly expecting sudden doubts and second thoughts to come creeping up. But none came. She'd already put so much thought into this... She knew what she wanted. She knew more thoroughly than she ever had before.

Before she could answer, the door opened. Celestia stood just inside, the glow around her horn fading as she released her hold on the door. She didn't say anything, not yet. She just smiled warmly at both of them ... in the subtle way only Celestia could.

After indulgently basking in that smile for just a moment, Twilight turned back toward Luna. “Yes... Yes I am.” She felt her cheeks heating up a little, but struggled to maintain face in front of the two elder princesses. She had to exude an aura of calm surety, and definitely not the 'Twilighting' that might be expected of her in such a moment. “You two are like family to me.” Wait, no ... that had all the wrong implications. “Well, um, I mean, not really family ... because, you know, that would make it weird, but...”

Celestia reached up one gold-shod hoof and brushed it caringly along the edge of Twilight's mane. “I think we know what you mean.”

“Yeah, um ... well...” Out of long experience, Twilight repressed the urge to panic at this first hint of things not going absolutely perfectly. Instead, she took a deep breath, bringing a moment of precious clarity. “What I mean to say is that when it comes to starting a family, there's nopony I'd rather trust than the two of you.”

“Did you bring all of the requisite supplies?” Luna asked ... ever the practical one.

Twilight used her magic to hold open the flap of one saddlebag – the one closer to Luna. “I got everything you asked for!” She felt herself blushing again, and didn't even bother trying to hide it this time. The other side of her saddlebags could remain secret for now. “And ... a little extra.”

“Well come inside, won't you?” Celestia said. “Both of you. There's no reason I should be keeping the two of you waiting out here in the hall. Come in and make yourselves comfortable.”

As soon as the door closed behind them, Luna trotted toward her sister's bed. “Well, shall we begin?”

“Luna, please,” Celestia chastised. “You've only just arrived! Don't you think we should relax and settle in a little bit first? There's no rush. We have all night.”

“You have all night.” Luna gave her a sidelong glance. “I rescheduled as much as I could, but I do still have duties to attend to before morning...”

“Actually...”

Both sisters turned to look at Twilight the moment she spoke up, which made her falter for a moment, but she soon continued.

“Can I, um ... take a moment first? There's.... Well, there's something I wanted to put on first.”

Celestia gave another one of her warm, understanding smiles. “Of course. Go right ahead. You know where my private washroom is, don't you? Take all the time you need to freshen up.”

“But not too long,” Luna added.

As Twilight headed into the attached bathroom of the suite, she heard Celestia's hushed whisper: “What's that supposed to mean? What has gotten into you, Sister?”

And the answering whisper: “Can you blame me for being eager to begin? I have never before experimented with potions such as these, and...”

Twilight shut the bathroom door behind her, blocking out the sisters' conversation. That could wait ... and most of it was none of her concern, anyway. What she needed to do now was focus on herself. Thankfully, this was the perfect place for such a focus. The bathroom included a huge, alicorn-sized alcove surrounded by full-height mirrors on three sides. And despite now being an alicorn princess herself and even having her very own castle, Twilight couldn't help but feel a little thrill and standing where Celestia had stood every morning for centuries, preparing herself each day ... so many momentous, historic days began here...

No, she reminded herself. She couldn't get distracted with that kind of thinking. Those days were long gone. What mattered was this night. And even if this night didn't end up being all that historic, it was certainly momentous, at least to her. Tonight would be the start of her new family. A foal of her own. And she finally felt ready for it. This was the night. This was finally the night for her.

She slipped the saddlebags off and gave herself an appraising look in all three mirrors ... even turning sideways in order to check that all-important view from the rear.

Perfect. Absolutely perfect. She'd prepared herself ahead of time, of course, with a visit to the spa in the morning, a tension-releasing massage in the afternoon, and a quick trip to one of the best salons in Canterlot before heading into the castle, just to make sure her mane was in pristine condition. She was groomed immaculately, and her purple fur gleamed even under the unflattering glare of the mirror alcove's lights.

Now for the rest... The part she couldn't be seen walking through Canterlot Castle with.

The other side of her saddlebags, the side she hadn't yet opened, contained mostly silk and lace ... all of it in a shimmery, silvery color that contrasted perfectly with her own coat while somehow managing to conjure visions of both Celestia's shining coat and the glimmers in Luna's mane. Marvelous, really, how well it suited all three of them. Truly made for this purpose. It was a masterpiece.

First, she slipped the long, thigh-high stockings up her hind legs. They went all the way up, stretching tight just as they rubbed up against her teats down between her legs. Perfectly tailored to her stature, of course. Then a matching pair for the front, not as long, but just as beautiful. It had been made very clear to her that she mustn't confuse which one was made for her left or right hoof, since they were sewn very exactingly. Twilight had made an inconspicuous little mark inside the elastic lace strap at the top of each, just for that reason.

Then a lacy, frilly saddle. It would be useless to actually try and ride on, of course. That wasn't what it was for. It was merely a fashion accessory ... one that would bring to mind visions of being on her back to anyone who saw it. To go along with it, there was a silvery lace halter to fasten around her muzzle and back around the back of her mane with a bow. Again, no practical purpose. This was no bondage gear or anything that would actually restrain ... merely a way for her to make the suggestion of giving over control. Then there were a couple little garter straps, connecting the top of her hind leg stockings to the back of her decorative saddle. She wasn't sure what the purpose of these was – the stockings held themselves up just fine without any help – but apparently, it had something to do with 'framing' and 'drawing the eye to what's important'.

And, of course, there was the last part, the important part that everything was supposed to draw attention to. A shimmery pair of panties, and quite small. When she pulled them up her hind legs and tugged them into place with her magic, they scarcely covered her vulva, and hardly anything else ... which was distinctly odd, of course, since hardly anypony bothered covering up such things in normal day-to-day life. But once again, the purpose wasn't practical, but decorative. She wasn't sure the idea made sense, but it had been insisted to her that covering something up would make it more desirable and more special when finally revealed.

With a careful eye for anything poorly fitting or worn incorrectly, Twilight examined the effect in the mirrors. She looked like ... well, she hadn't seen anything like this since she was a filly, since she snuck in to read the magazines her brother hid under the bed. And even that hadn't been quite like this. Those other mares had looked tawdry, like they were wearing costumes – cheap imitations of ... of, well, this.

Yes, this was perfect. Hopefully the royal sisters would like it.

Levitating the bag of potions in front of her – she didn't dare mess up her outfit by trying to wear the saddlebags on top of it – she headed back for the bathroom door, back to where the sisters would be waiting. Was she ready for this? Truly ready? Yes. Even if she had to admit to a little nervousness, that was just part of the experience. She was going to do this, and no backing out now.

When she opened the door, Celestia and Luna didn't seem to notice at first. They were deep in a whispered conversation, with much quieter whispers this time. Twilight couldn't make any of it out. They were lounging on Celestia's little nest of cushions by the fireplace, with all their royal regalia removed. And without all of that, the two of them looked so much more like normal ponies ... if ponies so regally tall and with flowing, coruscating manes could ever look 'normal'.

She gulped, then took yet another deep breath. “So, um...”

Both of them suddenly turned to look at her, their eyes going wide.

It made her cheeks heat up again, but she forced herself to continue anyway. “How do I look?”

Celestia just stared, her mouth slowly dropping open. It almost seemed as if her tongue was ready to fall out and as if she was about to start drooling, but she did manage to restrain herself from that.

“See,” Luna said to her sister. “I told you that you would not regret agreeing to this...”

Twilight spun in a slow circle to show it off from all angles. “You like it?” she asked ... almost as much just for the purpose of teasing as to actually get an answer.

Not that such an answer was to be forthcoming, anyway, at least not from Celestia. She still sat there and stared, struck speechless by the sight of her.

But Luna, at least, retained the ability to speak. “You look lovely, Twilight. Scrumptious and adorable.”

“Oh...” Twilight paused in her spin, now with her flanks facing the sisters. She looked at Luna. “Adorable wasn't quite what she was going for, but okay...”

“She?” Luna tilted her head slightly to the side. “Who?”

Twilight glanced away for a moment before answering. “I suppose I should confess ... I told my friends about our plans together. And once Rarity found out, she insisted on making this especially for the occasion.”

“It's wonderful. Truly one of her best works, wouldn’t you agree, Tia?”

The only response Celestia managed to give her sister was a slow nod. Her eyes remained fixed on Twilight the entire time.

“So,” Luna said, “shall we administer the potions?”

“Yes!” both Twilight and Celestia said ... both of them too quickly, too eagerly. Both of them glanced away, their faces reddening.

Celestia and Twilight both followed Luna over to the empty sideboard table, where the Princess of the Night gracefully took the saddlebag out of Twilight's magic and into her own. As she carefully laid out all of the potions in a neat row, Twilight and Celestia snuck glances at each other over her back.

“Female fertility potion,” Luna read carefully off of one label. “Take after sunset. Guarantees conception if inseminated with viable seed before sunrise.” She slid that bottle over in front of Twilight. “This one is for you, I believe.”

Twilight barely even noticed the bottle. She was perfectly familiar with it anyway. Much more interesting was the way she caught Celestia glancing back at her stocking-clad hind legs.

“Male fertility potion.” Luna slid a pair of bottles in front of herself and Celestia. “Increased volume and virility of semen. Effect lasts for three days, or until the increased capacity is expended. Do not use more than once per month, and under no circumstances allow dragons to consume this potion. Not for use on livestock or domestic animals.” She quirked an eyebrow. “Interesting... I cannot help but wonder what does happen if a dragon should consume it...”

While Twilight would normally be the fist to get engrossed in speculation about such a mystery ... she was rather more fascinated with what she could see under Celestia's tail if she craned her neck back far enough. Was ... was that a wink?

“Temporary futa potion, double strength.” Luna slid another pair of bottles in front of herself and her sister. “Grants females male genitalia in addition to their own for the duration of two orgasms. Not recommended for use by males. Consult your potion-maker if resulting genitalia persist for more than four hours. Should not be used by ponies with heart conditions or in combination with any other potion.” Luna frowned at the bottle in front of her. “Twilight, are you certain that it's safe to combine this potion with the male fertility potions, or even the female fertility?”

Twilight didn't answer. She was busy not staring at Celestia's curvacious alabaster ass. Celestia was looking at her, and she couldn't be caught staring.

“Are you two even listening to this?” Luna snapped.

“Yes! Yes, of course!” Celestia blurted out. “Very important and interesting!”

Twilight managed to formulate a slightly more useful response: “Don't worry, I asked Zecora about it. That warning is just there to stop you from combining it with any gender-swapping or species-transformation potions, which would make it give some very unpredictable results. She's extremely knowledgeable about these kinds of things, and she's assured me that this combination of potions is perfectly safe. And that it gives us basically guaranteed success.”

To underline her confidence in the potions, Twilight levitated her own bottle in front of her and quickly downed the small vial, sucking it dry. She'd tossed it back quickly in case it tasted horrible ... but it actually wasn't bad at all. The flavor reminded her of a fruity tea ... maybe with a hint of cinnamon in it. Immediately, she felt an odd warmth surge down her throat, spreading inside her and flowing to every part of her body ... until it swirled around and seemed to settle in a deeply abiding way deep inside her belly. It had a few other effects as well ... the most noticeable of which was that her pussy began winking even more fervently, quickly soaking through her shimmery silver panties. Rarity would be appalled. She'd said something about this fabric being incredibly expensive and difficult to acquire ... but the feeling of the supple fabric gliding against her pulsing clit was more than worth it.

Celestia and Luna glanced at each other for a moment, then both raised their own bottles – the futa potion first. They drank them together ... and from the looks on their faces, this potion didn't taste nearly as pleasant as Twilight's had.

But the results... Nopony could argue with that! Before Twilight's eyes, both sisters began to sprout some very interesting developments between their hind legs. At first just little nubs, something Twilight would never have noticed if she hadn't been watching for it, if she hadn't been a bit shorter than them and able to see under their bellies more easily. But those little nubs developed quickly, rapidly growing into very respectable sheaths, with mouth-wateringly smooth round balls hanging behind them. Twilight didn’t even bother trying to hide her interest now. She stared blatantly. As long as she prevented herself from drooling over them, she'd consider it a win. Only ... the potion she'd taken must have been having some mental effects as well, because keeping herself from drooling over these very new, very male endowments was quite a bit more challenging than she'd thought it should be.

But that wasn't all. Both sisters then downed their male enhancement potions.

Twilight hadn't expected much external signs from that potion. After all, her own fertility potion hadn't done much that would be visible from the outside. The desperate winking of her pussy against the inside of her panties would be the only external clue.

But the male fertility potion ... well, it was quite obvious whether they'd taken that or not. As Twilight stared, her eyes widening, Celestia's pale pink balls swelled, growing until either side of them squeezed against her inner thighs, leaving her sack to dangle ponderously between her legs. And Luna's dark blue balls underwent the same effect, if anything, growing even bigger than her sister's. While the two of them might have been able to walk the halls before now and not have their swinging balls noticed if they were lucky ... now there was no chance. No chance at all. Each of them was now burdened with two huge orbs down between their legs ... and even their sheathes seemed to have grown a little wider and a little fuller.

As inconspicuously as she could, Twilight licked her lips.

Celestia's eyes met Twilight's. And after that moment of connection, it was inevitable that the two of them would come together, despite having to go around Luna to get to each other.

The two of them slowly approached each other, each of them staring as if seeing the other for the very first time. When they met, they at first just bumped their muzzles softly against one another ... which seemed to startle them out of their daze. It did so for Twilight at least. Blinking, she came closer, sliding her neck along her longtime mentor's, then reaching up to caress her hoof over the silky fur of Celestia's withers.

Celestia began touching as well, beginning with a tender touch along Twilight's mane and up behind her ear ... but definitely not ending there. Her hoof wandered down along Twilight's neck, over her frilly saddle and folded wings ... and even managed to reach all the way back and rub along her flank. But even Celestia's long leg couldn't reach all the way back to where she so obviously wanted to touch. And it didn't escape Twilight's notice that a thick pinkish nub began protruding from Celestia's sheath, growing and dropping into a rapidly expanding cock of very generous proportions.

Meanwhile, though, Luna reared up on her hind legs, staring down at herself and her new sheath ... which did not produce anything at the moment. “I must confess,” she said, “I do not quite understand how to make this new appendage work. Is some additional spell required?”

Celestia pulled back away from Twilight, giving her a smug wink ... and then without warning, she ducked her head down below her sister's belly and began licking – first along the rim of Luna's sheath, and then down down, running her tongue over the vast curves of Luna's balls.

Twilight hastily joined her, deciding instantly that she would not be the one to point out anything having to do with incest ... but also that she would not put the two sisters in a position to need any such thought. Obviously, it didn't count if it was just part of a threesome, and Twilight could provide that. It was the least she could do, after everything they'd already agreed to help her with tonight. She joined Celestia, first tonguing along the edge of Luna's sheath, tasting the little bit of moisture Celestia left behind there, before joining her mentor down at Luna's sack. With how much the potion had expanded things, there was plenty of room for both of them to nuzzle and lick the deliciously smooth skin and feel the full, hefty weight behind the massive balls.

Even as they both kissed and licked to their best ability, though, Twilight felt something begin to caress her ... something delicate and feathery ... Celestia's wing! It traced around the fancy saddle, up and down the curve of her back, and then became a little more adventurous. First it was just a little bit of curving around her sides, teasing around at her underbelly. But then it was running along her flank, then tracing the curve of her ass ... and finally, Celestia blatantly began rubbing the rib of her wing right up and down between Twilight's cheeks, massaging the bulb of Twilight's pussy through her now-soaked panties. And of course, that produced a very predictable reaction in Twilight's body. She winked like crazy against Celestia's wing, and despite – or perhaps because of – the distraction of Luna's full, heavy balls against her lips, her pussy simply poured out her arousal, soaking her panties so much that they began dripping down her thighs and onto the floor.

Twilight wasn't the only one whose body produced a predictable reaction, though. While she and Celestia were distracted with each other, Luna's dark blue cock had emerged. The two of them only noticed it when it finally hung down and draped heavily over both their faces.

That only gave them more to play with. Both of them tilted their heads up, tongues outstretched and ready for Luna's massive shaft to lay across them. Twilight was proud to take responsibility for Luna's tip, taking it as far as she could into her mouth. Of course, that wasn't terribly far, not with a futa mare as well-endowed as Luna was when even partially erect. Celestia took care of the rest, though, running her open mouth up and down the remaining part of her sister's cock with every evidence of utter bliss.

It was at that moment that Twilight began to understand why the sisters had agreed so readily to both participating in this, and at the same time. She wasn't about to ask inopportune questions about it, though, and not simply because her mouth was quite full of warm, musky alicorn cock. Celestia's wing was still hard at work, now tracing little circles around the hot wet bulge in Twilight's panties. It made her whole body tingle, made her fur stand on end ... and she was not about to do anything that might risk stopping a feeling like that!

Quickly, Luna's cock grew stiffer and swelled even larger ... to the point where Twilight couldn't keep it in her mouth anymore. Pulling away from her tip with a desperate gasp, she instead joined Celestia in running her tongue up and down that warm, dark blue shaft, exploring every contour of its increasingly hard length. And now that she'd turned her head a little, she could see under Celestia's belly ... to spot the throbbingly hard pinkish cock bobbing underneath her. Twilight's mouth watered at the sight ... which only made her efforts at sliding over Luna's cock all the more effective.

For a moment – just a brief moment – Celestia took her mouth away from her sister's cock. “Are you ready, Luna?”

Luna only gave a throaty moan. But that moan sounded at least a little bit affirmative. She slowly lowered herself back down to all four hooves and came around behind Twilight, who raised her tail high over her back in order to better accommodate her.

Celestia joined her there, and for a little while, both of them simply enjoyed the view, running their hooves – and then their mouths – up and down and all around the compact little curves of Twilight's ass cheeks. But neither of them were satisfied with that for long. Soon, Twilight felt both of them working their way upward, felt their teeth slightly pinching for a moment as they sought the straps of her panties.

And then her panties began pulling down. Twilight had thought they would use magic, not something so ... intimate. But she couldn’t deny how wonderful it felt to have their mouths gliding down over her fur. Rarity's carefully prepared and tailored panties that had taken so much effort and so many intimate measurements to tailor ... they slowly peeled away from her soaked pussy lips. It triggered a whole new wave of desperate winking, her clit pushing out and rubbing against the thin, shimmery fabric as it slipped away. She felt so open, so exposed, as the two sisters slid the panties the rest of the way down her hind legs ... and yet, also so desired. She could feel the intensity of the way they gazed at her back there, blatantly staring where ponies would normally consider it impolite to even glance. And that only made her wink all the more, flashing her hot inner walls out against the cool air in Celestia's bedroom.

As interested as Celestia and Luna obviously were, they did not dart straight back up after Twilight stepped out of her panties. Instead, they each slowly and luxuriantly licked and nuzzled their way up her legs, mouthing and kissing her through the stockings in nearly perfect unison. Had they ... had they done this kind of thing before? They seemed so practiced, so skilled...

And when they worked their way up above her stockings... Twilight shivered a little, her tail involuntarily twitching higher even, though it was already flipped up over her back. She could feel each of them breathing against her now-hypersensitive fur. That was the only part that wasn't quite in unison. Against her right cheek, Luna's breath came slow and steady ... but Celestia's breath against her other side came as an eager whuffling that came closer and closer to...

Twilight gasped as both of them – still in unison – pressed their warm, soft lips against the eagerly winking bulb of her pussy. Already, that was enough to send sparkling waves of pleasure all through her, and they were only getting started.

And oh, what thousands of years of experience did for them... Two tongues slowly traced up either of her pussy lips, barely touching. Yet, the lightness of their touch actually somehow made the sensation more intense. Twilight's hind legs went stiff, instinctively spreading out a little wider, giving them more room to lick ... and more room for other things.

Because as incredible and overwhelming as it was when they slowly intensified their licking, when they took turns sliding their tongues up through her slit while the other circled her clit, when they kissed each other right against her vulva and let her winking pussy join in, when they traded her outthrust clit back and forth between their mouths without ever letting it touch the cool air ... through it all, Twilight never forgot what else was in store for her. She couldn't see from this angle, but her imagination still swam with visions of those two big cocks, now achingly hard, each of them flanked by enormous balls bulging out from between the sisters' hind legs. Just the thought of that – not to mention the attentions of their tongues – made her juices flow so freely that the two sisters must have been getting their whole muzzles soaked in it. Everything certainly felt quite slick and juicy back there, sliding so freely as the two sisters nuzzled ever closer to each other underneath her tail.

Celestia was the first to pull back. When Twilight turned her head around to look, she found the leg-quivering sight of Celestia's muzzle literally dripping with her juices – so soaked that syrupy drops fell away from her lips with every movement.

“I believe she's ready, Sister.” Celestia licked her lips slowly ... which didn't really accomplish all that much cleaning. There was just too much. “In fact, perhaps we've gotten slightly carried away?”

Slowly, seemingly with great reluctance, Luna lifted her muzzle up from between Twilight's cheeks as well. If anything, she was even more coated in juices. At first, Twilight thought she was going to say something in reply – probably some very practical, businesslike quip – but no. She said nothing. Instead, she reared up and lunged forward, her forelegs sliding up and over Twilight's rump, her chest sliding up into the seat of the frilly saddle ... and the immense warmth of her big blue cock pressing up against Twilight's pussy lips.

Twilight's eyes went wide, and her vision clouded a little around the edges. That warmth! That pressure! Maybe her fertility potion was affecting her more than she thought, because she felt as if she could have nearly fainted just from this first touch.

“Oh...” Celestia pursed her lips together. “Very well, then... After you, Sister.” She came up around Twilight's side and nuzzled her cheek. “Treat her well, Luna.”

“I will.” With a slight grunt of effort, Luna pushed her hips forward.

As her pussy lips parted open, stretching around Luna's massive tip, Twilight trembled in place. Her breath left her, and she seemed unable to draw in another. She couldn't move at all as she felt Luna's shaft begin sliding against her inner walls, sharing the older alicorn's heat so generously inside her, spreading ever deeper as more and more of that stiff shaft slid through her tightly stretched entrance. Visions flitted before her, more real than what her eyes could actually see: a giggling new foal of indistinct color but very clear and sparkling eyes staring up at her in filial adoration, her own belly swelling wide and ponderously full of new life growing deep within, the enormous blue bulges of Luna's balls and the endless potent seed churning up from inside them that would make all of this possible...

Luna's forelegs gripped tightly around Twilight's sides, and her breath came in desperate heaves as she pulled the two of them closer together, filling Twilight to an extent she'd never felt before.

Twilight was no virgin, of course. She'd had her share of amorous encounters with stallions – and even a few mares – in Ponyville and elsewhere. But never without double and triple protection against pregnancy, and never with ponies she cared about as much as Celestia and Luna. This, this warm fullness that filled not only her pussy but her heart – this was new. It soothed and relaxed her body, erasing the last of her nervousness even as her pussy tensed around the shaft slowly filling it.

When Luna had gone as far as she could – the huge warm swells of her balls pressing against the back of Twilight's thighs – she paused there, letting Twilight soak in her marvelous warmth, giving her body a moment to adjust to the huge new presence inside.

She looked over at her sister. “You know... I never had a chance to enjoy your new endowment as you enjoyed mine...”

Smiling, Celestia leaned in close to Twilight's ear. “And what about the faithful student? Would you like a taste?”

Twilight's pussy lips winked fervently around the base of Luna's cock. “Yes,” she breathed, simply and eagerly.

As Luna began slowly, sensuously humping against Twilight's rear in gentle rocking motions, Celestia reared up just like Luna had before, resting her forehooves on Twilight's withers. Celestia's pale pink cock rose spectacularly right in front of Twilight, with her gloriously oversized balls bulging out prominently beneath.

Without even thinking about it, Twilight leaned just a bit forward and stretched her mouth open over Celestia's tip. It wasn't an easy fit. The warmth of Celestia's cock filled her mouth, and the smell of her filled her nose. A comforting, familiar smell ... and yet with a hint of spicy musk that had never been there before. Twilight breathed in deeply as she slid her mouth down, at least until the bulk of Celestia's tip filled the back of her throat. So virile, so potent ... that male fertility potion was simply incredible. Or was it the effect of her own fertility potion, making her more sensitive to such things? She slid her tongue along the underside of Celestia's tip, pleasing her old teacher to the very best of her ability.

Of course, she wasn't the only one to employ her tongue... Luna hunched herself over the frilled saddle, driving herself even deeper into Twilight's magically receptive pussy. And once she'd gotten in close enough, she slid her long, elegant neck down along Twilight's, craning forward to run her own tongue up and down the rest of Celestia's shaft.

And as if the taste of her sister's cock had invigorated her anew, Luna began thrusting hard into Twilight's pussy – deep, solid pushes that made Twilight feel like she was going to swell to bursting with each one ... and progressively getting faster and faster.

Soon, Twilight just couldn't take it. She pulled her mouth up off of Celestia's tip suddenly, bursting with the need to cry out. She couldn't help it – the sound just wanted to come out of her throat. She'd never felt like this with a stallion before! With her mouth free and dripping, she let the loud – and hopefully not exactly shrill – moans come out freely. It was all she could do, given the way Luna was filling her, the way Luna was moving inside of her.

Luna, though, seemed as cool and collected as ever ... or at least nearly so. Despite how ardently she was pushing herself into Twilight, she seemed to have no trouble at all sliding her tongue all the way up to Celestia's tip the moment Twilight let it out of her mouth. Luna took her sister's cock in her mouth quickly and effortlessly, making it look easy. And she went deep.

Twilight gasped out loud, not only from the feeling of Luna's thick sheath pressing tightly against her pussy lips once more, but from the sight of Celestia's cock disappearing into Luna's mouth. As she watched in gape-mouthed amazement, she could see the thick bulge traveling up through Luna's slender neck. And yet, it didn't seem to bother Luna at all. She didn't cough, she didn’t gag, she didn't even miss a single thrust in her rhythm of moving inside Twilight's pussy.

Belatedly, Twilight followed Luna's example, mastering herself – and the intense sensations coursing through her – enough to bend her head down and take Luna's place licking the base of Celestia's cock.

But if she thought she could stay there, she underestimated Luna's sisterly love. Twilight only had time for a few sensuous licks against Celestia's thickly veined base before she found her lips butting up against Luna's in some kind of insane, intense, incestuous, incredible kiss.

She wasn't about to stop Luna from going all the way. Who was she to stand in the way of such an impressive accomplishment? Who was she to stand in between these two sisters' love for each other? Well, except for the way she was literally standing between the two of them ... or doing her best to stand. With the weight of two alicorns' forelegs on her back and with the massive warmth of Luna's cock surging back and forth inside her, she wasn't entirely sure she'd manage to remain standing. They weren't that heavy, but every time Luna pushed all the way in and Twilight felt like her whole body was wrapped around that magnificent cock of hers, she wasn't sure she'd be able to hold up even her own weight for much longer.

But Twilight wasn't completely left out when it came to offering her mouth to Celestia, even though Luna was already eagerly bobbing her head up and down just above Celestia's sheath, with that whole enormous cock lodged deep in her throat. When in her long life had she learned to do that? But no, even though Luna was monopolizing Celestia's cock as completely as she was taking Luna's, she still had one little consolation prize. Or rather, two ... and for that matter, they weren't 'little' by any stretch of the imagination.

Celestia's immense balls hung down right in front of Twilight, just within reach. And what better invitation could she ask for? Leaning forward and down just a touch even as Luna thrust into her, she delicately nuzzled her nose against the deep cleft between those two pale pink balls. She licked slowly up the broad, smooth curve of one, savoring the sheer incredible massiveness of it. Each one of them was huge on its own, and taken together, Celestia's whole sack would be bigger than Twilight's head.

What would it feel like to have those gargantuan balls emptying their magically enhanced capacity inside her? She moaned a little against the firm curve of the other bulging ball as Luna pressed deeply inside her, Luna's own hefty pair squeezing tight against the back of Twilight's thighs. Soon, she'd know, wouldn't she?

Very soon, perhaps... Because having her sister's cock plunging deep into her throat seemed to agree with Luna. Her thrusts were getting more urgent, going even deeper and staying in for even longer. What breaths she could squeeze around Celestia's cock came in subtle little grunts of effort at the peak of each thrust into Twilight's pussy. Twilight's eyes drifted closed as she imagined the hot flood that would soon be bursting out inside her.

But Luna wasn't the only one nearing her climax. “Sister!” Celestia cried out between increasingly desperate breaths. “I'm... I'm...”

Even though Luna kept right on suckling around the rim of Celestia's sheath, Twilight paused her licking for a moment, looking up at Celestia's face as well as she could, even though the Sun Princess's huge balls kept bumping gently against her cheek. “Wait!” she cried out as loudly as she could, the strain of Luna's rutting aiding her voice, even if that did make it sound like a little bit of a squeal. “Please! Don't waste it!”

Celestia must have taken that very seriously, because she immediately pulled herself away, sliding her long cock all the way out of her sister's mouth as she slipped back down to all four hooves.

Twilight's eyes went wide when she saw how massive the tip of Celestia's cock had grown. It was as big around as one of her hooves, flared out like the mouth of a trumpet. Her gaze followed its bouncing motion as Celestia quickly leapt around behind both of them.

But the sight of Celestia's flare had brought to mind exactly what the steadily growing pressure and tightness deep inside her own pussy must be. Luna's flare, every bit as massive as her sister's, but deep deep inside Twilight's pussy ... where it pressed right up against the entrance to her womb, gently but insistently spreading that tight little opening wider, preparing her to receive the flood that would soon be coming ... very very soon.

Celestia danced from side to side behind them. “Please, Sister!” she cried. “I can't hold myself back for much longer!”

“Neither...” Luna bit down at the base of Twilight's mane, holding her and claiming her like a feral stallion. She grunted through her clenched teeth, “Neither ... can I!”

Celestia made an odd little keening sound in her desperation. “Twilight, what should I—?”

But Twilight was too far gone. That massive flare knocking at the entrance of her womb was triggering some powerful effects from her fertility potion. “Don't...” She sucked in a deep, shuddering breath. “Only two... Don't waste...”

Luna's rhythm broke. A new weight staggered both of them forward. And even as Luna bit down against Twilight's mane, she let out a little squeak – a surprisingly girly-sounding bit of a squeal. Celestia had mounted her! Twilight looked back over her shoulder, her mouth gaping in open astonishment. It couldn't be ... it couldn't be...

“Sister!” Luna said desperately, releasing her hold on Twilight's mane. “What do you think you're—?”

With a deeply relieved sigh, Celestia slid her spit-slick length all the way into her sister, pushing into her as deeply as Luna was inside Twilight. Then another small thrust, another, each one pushing Luna forward in turn, moving her cock inside Twilight's pussy.

After only a few short thrusts, Celestia pushed herself in as far as she could, stopping there and gripping her sister's body tightly against her own.

“Tia!” Luna cried out, her voice strained ... but also full of love.

A soft but very deep shuddering groan was Twilight's only clue that Celestia was cumming inside. Just that illicit fact was almost enough to drive Twilight over the edge ... so when Luna herself came with a whimpering cry, Twilight didn't stand a chance. From the very first throb of Luna's cock, Twilight's pussy was already squeezing down, convulsing, sending hot rivers of consummate pleasure flowing all through her body. When the first thick gush of cum came flooding out, her body was ready for it. Her womb was open and receptive, eager for the streaming cum to flow into and swirl as it flooded her. She instinctively arched her back, tilting her ass slightly upward to position her pussy lips at an upward angle against Luna's sheath, ready to take everything she could and not spill a single precious drop.

The next burst came. Twilight could feel it jetting out against her, splashing against her very deepest, innermost places. And the sheer mass of it! Each individual throb delivered more cum inside her than she'd ever gotten over her whole lifetime. By the third, her womb was stuffed full and the excess was straining against the perfect seal Luna's flare made so deep inside her tightly stretched pussy.

And it was only beginning! Each successive burst of cum inside her was growing more powerful still, not less! Her belly strained with the enormous load pumping into her, swelling wider, making her look and feel as if her pregnancy was already well underway. Only then, finally did the pressure build up enough to begin spurting past Luna's flare. The sloppy heat of it swelled and swirled out between Luna's shaft and Twilight's inner walls, flowing up through her in waves ... and when it reached the still-winking lips of her pussy, her instinctual preparations meant nothing. Hot alicorn cum spattered out onto the floor between their legs, too much for Twilight's body to contain.

There was no cause to cry over the spilled cream, though. Luna was still pumping more into her, prolonging her orgasm into a dizzying spiral she thought she might never escape from ... and she never wanted to escape from. Her whole body seemed to glow from the inside out. What a magical way to start a new life inside her... would this endless bliss last all the way until the new foal was born? In that moment, it seemed possible.

The touch of Celestia's trembling hooves against her folded wings reminded her that Luna and herself weren't the only ones still going. If anything, from the way Luna's belly swelled against Twilight's back, Celestia's orgasm was even more prodigious. Twilight moaned again, and not even from the pleasure of her own orgasm, but from the thought of Celestia stuffing her sister full of that wonderful life-giving cream ... even as Twilight swelled into a little cream puff herself.

Eventually, though, after a torrential orgasm that lasted longer than some of Twilight's previous partners had been able to even stay inside her, Luna's orgasm finally ebbed, as did Twilight's own, to her mild disappointment. After lasting that long, it really had seemed as if it might go on forever.

Celestia seemed to have finished first. With a very satisfied-sounding groan, she let herself slip down off of Luna's back.

Twilight's ears perked and her cheeks flushed when she heard the splattering sound against the floor that followed Celestia's cock plopping out of her sister. There was so much of it...

Nuzzling up against her sister's moon-emblazoned ass cheek, Celestia gave a satisfied sigh. “Oh Sister, you look so cute like that. Everything between your legs is white now, you know.”

Luna took the time to nuzzle Twilight's cheek and give her a little kiss before turning her head around and responding to that: “Your whole body is white, Tia. What am I to make of that?” She gave one last, squishy thrust into Twilight's pussy, despite the way her cock was softening. “And if you think what you've done with me is impressive, just wait until you see—” she slid off of Twilight's back, pulling out suddenly “—this!”

There was no mistaking the thick, sticky warmth that flowed down Twilight's inner thighs. She gasped at the feeling, her tail still raised high. At least the intense pressure deep inside her lessened a little, even though her belly barely slimmed back down at all. Even as absurd amounts of Luna's essence drained out onto the floor, she still felt stuffed, filled to the brim ... and no doubt considerably heavier than she'd been a few moments ago. The relentlessly inquisitive part of her yearned to dash for the nearest scale and confirm that. But thankfully she was able to restrain herself ... if only because her legs felt too weak and trembly to get that far.

“Mmm...” Celestia nuzzled up against Twilight's ass cheek as well. “Truly impressive, Luna. Magnificent, even. Wouldn't you agree, Twilight?”

Twilight would have liked to make some quippy and yet erotic remark in return, but when she tried, all that came out was a distressingly incoherent and yet very satiated whimpering, mumbling mess.

Celestia giggled softly. “Sister, I'm afraid you may have broken my faithful student.”

“I am certain she will recover. And I must make a confession – I myself have a certain ... understanding of how she feels at this moment.”

“I do hope she recovers before these potions wear off, though.” Celestia made a tisk-tisking sound with her tongue. “I'm certain she would prefer the two of us to have an equal chance at fathering her new foal. Isn't that right, Twilight?”

That was enough to get through to her. Twilight suddenly twisted her head back around to look at the two of them. The quick movement made her dizzy for a moment, and she staggered a bit, her hind hooves splashing and slipping in a shallow white puddle. Rarity's poor stockings, getting soaked from above and below... “Please!” she cried as soon as the fuzziness in her head cleared a little. “Please yes!”

“Of course I will.” Celestia smiled sweetly at her. “But I'm afraid...” She turned her body to the side a little and glanced down under her own belly, where her cock hung down limply. “I ... I may need a moment or two of recovery myself, actually.”

Twilight wasn't the only one staring at that swinging length of mare cock. Luna looked down under her sister's belly and licked her lips. “Sit down there at the edge of the bed, Sister. I believe Twilight and I may be able to speed your recovery...”

Author's Note

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Celestia and Luna

“Sit down there at the edge of the bed, Sister. I believe Twilight and I may be able to speed your recovery...” As Luna said it, she nudged Celestia forward with a none-too-gentle nuzzle against her backside, following it up with a playful nip.

Twilight smiled at the sudden jolt that visibly ran through Celestia's body at the pinch of her sister's teeth on her ass. Celestia trotted over to her massive bed with a springy, showy gait ... and also a reproachful look back over her shoulder.

Luna, though, seemed unrepentant, her eyes holding only a deep hunger for her sister. Literally taking Twilight under her wing, she followed Celestia to the bed, bringing Twilight along with her. “Come with me, Twilight Sparkle,” she said in a tiny whisper, “and you will have another chance to employ your throat. I believe you will find success far more easily when she is flaccid. 'Tis how I first learned the skill.”

Twilight bit her lip slightly. Oh, if only her younger, more panic-prone self could see her now ... about to get a lesson in fellatio from Princess Luna herself. And the subject of that lesson...

When Celestia turned around and settled down onto the edge of the bed, spreading her hind legs out in front of her, Twilight's breath caught in her throat. Even with her thick pink cock drooping down in front of her balls, the sight of that incredible package – Princess Celestia's package! – was almost like the feeling of awe she'd gotten the very first time she'd seen Celestia raise the sun. Only ... instead of making her mouth go dry, it made her mouth water nearly to the point of drooling; instead of making her stand in stunned awe, it drew her inevitably nearer.

Celestia smiled down on her as she approached. “Oh Twilight... I never could have imagined I'd see— Oh! Oh my...”

Whatever Celestia's warm sentiments would have been, they were lost to time as Twilight eagerly caught the drooping tip of her former mentor's cock on her tongue, then let it slide right up into her mouth. The taste of Celestia's leftover cum filled her mouth, accompanied by the tangy aftertaste of Luna's nectar still coating it. She looked up into Celestia's eyes, letting the love flow between the two of them as she began swallowing down that soft pink length.

And swallowing was exactly the right word. Though still heavy and warm against her tongue, Celestia's cock was no longer firm enough to simply plunge her head down against. Doing so would only have bent it. Instead, Twilight had to actively suck her former mentor's cock, beginning to make big gulping swallowing motions as soon as she felt the soft warm tip against her throat.

With every gulp, she managed to pull it deeper, packing her throat full of Celestia's soft, warm girth. And this time, there was no struggle, no choking and gagging. It felt almost like she was drinking it down, except that it filled her so completely and stayed right where it was.

Celestia reached down and ran her hoof over Twilight's cheek, following the side strap of the lace halter. “Oh Twilight, you're so ... so... Mmm...”

Finally, Twilight's lips kissed against Celestia's sheath, but that hadn't been the only thing that prompted Celestia's moan. Luna had nudged her way in beside Twilight and taken her own place down at Celestia's massive pink balls, gliding her tongue over their huge curves and nuzzling her way into every musky crevice she could find.

At the feeling of her sister's tongue in so delicate a place, Celestia let out a long, shuddering breath. Her cock grew firmer inside Twilight's throat, filling her to the point of discomfort, but Twilight forced herself to keep going, to keep bobbing her head up and down slightly in her former mentor's lap, to keep slathering her tongue over that thick and veiny base of Celestia's cock, to keep swallowing – massaging Celestia's length with her pulsating throat, even as her unchecked drool began dripping down around Celestia's sheath. Twilight's pussy – so recently and utterly satisfied – awoke and winked again, dripping a bit more of Luna's cum onto the floor behind her and making her tail rise involuntarily.

Celestia glanced upward a little, obviously noticing that upward twitch. “Oh Twilight...” Her cock stiffened even more, forcing Twilight to change the angle of her neck to accommodate it.

But Twilight was committed now. Her only response was to push herself down harder, rocking back and forth a little as she plunged down again and again onto Celestia's cock, pushing as if she meant to swallow even that thick pink sheath as well. Shifting a little to stand on only one front hoof, she brought the other up and used the soft, supple fabric of her stocking to caress Celestia's hefty balls, tracing around their bulging curves and holding them up against Luna's eager face. For a moment, she lost focus on her ultimate goal for the night. The fantasy of Celestia cumming down her throat, emptying those huge balls straight down into her as she drank down every drop of the thick cream ... it overwhelmed her, made her plunge her head down onto Celestia's ever-stiffening cock even more fiercely.

As Celestia's cock became completely hard, though, that fantasy broke down. Twilight's already-strained throat met its limit. She coughed uncontrollably, and a sputter of her own spit burst out around her lips, splashing up onto her own muzzle and dripping down onto Luna's face below. As another gagging cough rocked through her, she pulled her head up. Celestia's length slid solidly against the inside of her throat, all the way out, until her pink tip, dripping with bubbly spit and pre-cum, popped free from Twilight’s mouth.

For a long moment, Twilight simply stood, staring at that wonderful cock as she sputtered for breath, making up for the lack of air she'd been forcing on herself so recently. Without thinking about it, she wiped her sodden mouth with one forehoof, only thinking of the delicate fabric of the stocking after she felt its silky softness soaking up her cum-laden spit. She glanced up at Celestia and felt her cheeks heating. She'd failed. Luna was better at sucking cock than she was. Far better.

Even now, Luna was still as dedicated as ever, tenderly licking and sloppily kissing every last little bit of Celestia's bulging balls, even going so far as to press her cheek hard against Celestia's inner thigh so that she could tuck her muzzle up into the steamy little gap between white thigh and pale pink sack. And down under Luna's own belly, her dark blue cock was beginning to rise again.

But when Celestia looked back down at Twilight, she looked anything but disappointed. Perhaps it wasn't the look of admiration Twilight had been hoping for, but it was something better: a look of utter adoration, ready to give herself fully to her former student.

Twilight licked her wet lips slightly. “Um, is it okay if I... I mean, are you ready to...?”

Beckoning Twilight closer with a twitch of one forehoof, Celestia smiled down at her. “I am ready,” she said in a whisper barely louder than Luna's slurping sounds from below. “I want you more than I've ever wanted anyone before.”

Ignoring the indignant little sound Luna made in response to that, Twilight went to Celestia.

She carefully stepped over and around Luna, bracing herself up on Celestia's outspread thighs. Celestia's wet cock rubbed down over her chest as she climbed, and she leaned into it, sliding over her former mentor's length, letting it rub its way down her swollen belly, past the tightly stretched girth strap of her decorative saddle, down over the delicate sensitive skin of her teats. And all the while, her face drew closer and deliciously closer to Celestia's. Just at the moment their noses bumped together, Celestia's tip rose up between her cum-soaked thighs from behind. It seemed to find the perfect place so naturally and easily, despite the unorthodox position. Right away, Twilight felt its firm heat against her sloppily winking pussy lips.

For a long moment, the two of them stayed right where they were, their muzzles touching and gazing straight into each other's adoring eyes.

“I love you,” Twilight mouthed, almost silent, barely daring to put any breath behind it.

Celestia kissed her, their lips meeting in a soft, loving warmth that Twilight had only ever dreamed of. Had Celestia heard what she said? The heat of her lips, the gentle caress of her tongue as she parted them, and the slight moan she let out seemed to be the only answer Twilight would get for now.

And Twilight would have been absolutely satisfied with that answer ... but there was more to come. As the two of them kissed, drifting off into a dreamy appreciation of each other, Celestia wrapped her forehooves around Twilight's back. One came up high, stroking the base of her mane ... and the other went down low, tracing down the groove of her spine and along the hollow of her back just above her ass.

Then Celestia gently pushed Twilight downward.

Twilight couldn't help feeling it was like the warm sun coming out from behind a cloud. She basked in the feeling of Celestia's warm cock parting her already-filled pussy open again, flowing up into her, filling her. Aided by every kind of unspeakable slickness, her shaft glided perfectly against Twilight's inner walls. Twilight smoothly and slowly sank down onto it, taking Celestia's entire length in one gloriously gentle stroke, all the way down until her outspread ass cheeks came to rest against Celestia's thighs, Luna's starry mane tickling the dock of her pertly raised tail from underneath. And through that whole time, their tender kiss never broke. She never lost the touch of Celestia's warm, soft lips.

Not until Celestia broke the kiss, at least. She slid her cheek along Twilight's, even as she held their bodies tightly together. When her muzzle came up next to Twilight's ear, she whispered even more quietly, “I love you too, Twilight.”

With a sudden gasp, Twilight lost it. She nearly orgasmed again on the spot. And Celestia must have felt the urgent squeeze from Twilight's pussy, because she answered it with a twitch of her cock inside.

“Are you ready?” Celestia asked in a more normal voice – but still tinged with unfathomable depths of love.

Twilight wrapped her hooves around the back of Celestia's neck, burying her face in that marvelously flowing mane. “Yes!” she breathed out desperately. “I want it – I want your foals!”

Celestia stroked the back of Twilight's mane tenderly. And slowly, ever so gently, she used her other hoof to begin rocking Twilight's hips back and forth in her lap.

As their close, intimate motions gradually intensified, Luna grew bolder down below. Now not only did she lovingly tend to her sister's enormous balls, she also ventured upward from time to time, teasing Celestia's sheath ... even licking along the edges of Twilight's pussy lips where they stretched out perfectly round to accommodate Celestia's girth. She must have been licking up remnants of her own cum as she did so, but that didn't seem to hold her back in the slightest.

Twilight's pussy winked uncontrollably. She began rocking her hips all on her own – pushing forward and back, forward and back, desperate to feel Celestia's cock moving inside her more and more. The length of Celestia's cock seemed to touch everywhere inside her, and everywhere it touched it left a warm, tingling glow.

Celestia's hoof held her tightly along the curve of her lower back at first, but began drifting lower, following the garter straps down from the back of her saddle around to the curve of her ass. Twilight gasped a little when the crook of Celestia's hoof grabbed around her cheek, squeezing its roundness. She rocked herself even faster then on Celestia's lap, feeling herself quickly building toward another climax, just from the idea of how much Celestia was enjoying her. And as she moved, Celestia's cock twitched and pulsed inside her, showing her in the most intimate way possible just how turned on her former mentor was getting.

But Celestia wasn't the only one with a growing arousal. After a moment's absence from below, Luna came up behind Twilight, rearing up behind her and sliding her way up Twilight's back. “May I, Sister?” she asked with every hint of formal politeness.

Celestia looked up over Twilight's shoulder at her sister with an indulgent grin. “Oh certainly. Please do.” She lifted Twilight up a little bit, pulling the smaller purple pony up off of her cock.

Twilight whimpered as that big, beautiful and warm cock left her gaping ... but only for a moment. Because that awful emptiness was filled a scant moment later with the heat of Luna's cock instead. Shuddering, Twilight sank down onto the other alicorn's cock, her eyes losing focus a little as she was once again massaged from the inside out by Luna's sensuous shaft.

Luna, gracious as she was, only kept her for the space of a couple heavy thrusts before lifting her up again, passing Twilight back to Celestia.

This time, Twilight didn't make the slightest sound of complaint when she found herself empty for a moment. Now she knew this for what it was. The sweet sense of anticipation more than made up for the momentary lack of warmth and fullness. And not only the anticipation, the fulfillment of it. Twilight felt as if she could melt as Celestia's cock reentered her. So slickly, so easily. Celestia pushed all the way into her in one effortless thrust.

For a time, Twilight lost herself in the sensuous embrace of these two sisters. Everywhere she looked, everywhere she touched, everything that touched her ... all of it was nothing but two of the ponies she most adored in the whole world. Every time they passed her back and forth between each other, she yearned to feel that other cock inside of her. Every time they pressed her tightly between each other, she felt as if she was the conduit for their sisterly love to flow through. Every time they kissed her, from in front and from behind, she felt like she was the luckiest, most enviable pony in the world. Both of the other alicorns breathed heavily into her mane, one from either side. She could swear that their oversized balls must be bumping into each other's down below her own body. She wished this would never end ... and yet at the same time she couldn’t help longing for the moment when it would all be fulfilled, when Celestia and Luna came again, filling her to the brim with their extra-potent seed.

And it seemed that moment might be coming... This time, after Celestia had taken her few passionate thrusts, she didn't lift Twilight up and give her back to Luna. Instead, she clutched Twilight even tighter, her breath burning against Twilight's neck as she slammed Twilight down again and again onto her ragingly hard cock.

“Sister?” Luna asked, her cock rubbing up and down between Twilight's ass cheeks.

“Too ... close!” Celestia grunted between desperate breaths. Before either of the others could react, she twisted around, taking Twilight with her and turning them both away from Luna.

Twilight mewled helplessly as Celestia pressed her belly-up against the bed, still thrusting into her but taking total control now. Giving herself up to it, Twilight arched her back against the soft golden bedsheets, giving Celestia a perfect angle to push into her again and again, harder and harder. Celestia braced her hooves on the bed to either side of Twilight's body, squeezing her in between them, holding her perfectly in place as she went in for a fully feral rutting, using Twilight's willing pussy to its fullest extent.

But Luna wasn't to be denied so easily ... and Celestia's change in position left her at a certain disadvantage from behind.

At first, Twilight didn't see Luna coming up behind her sister. She was to focused on staring up into Celestia's needy, desperate eyes. But then the look on Celestia's face changed – changed drastically. Her mouth suddenly opened into a silent 'o', and her eyes shot open wide. “Luna!” she said, her voice uncharacteristically squeaking.

“Yes, Sister?” Luna said, her face appearing above Celestia's shoulder as she slid into place over her back. She gave one solid thrust, which in turn pushed Celestia's cock into Twilight.

As Luna worked inside her sister's pussy, Celestia gradually bent down lower ... within kissing range. Twilight eagerly lifted her upper body just a bit, closing the last bit of distance and kissing her former mentor as lewdly as she could manage. Being filled with Celestia's warm cock was one thing, but this ... this was even better. Celestia's breaths came in little gasps, each one with a tiny little moan at the end as Luna plunged into her pussy.

Twilight ran her stocking-clad hoof through the fur on Celestia's neck, watching it stand on end as the ever-regal alicorn lost all semblance of control. Celestia moaned freely now, her breath shuddering loudly into the sheets right next to Twilight’s ear. Twilight held her close, even as she felt a little hint of drool next to her cheek. Her own insides tingled and burned around Celestia's flaring cock, even as she held the adorably overwhelmed alicorn close and tenderly. And there was only one thing that could douse that fire inside her...

“Do it,” Twilight whispered into Celestia's ear. “Cum for me. Cum for Luna. Please ... we want it... We want you so much. We want—”

With a loud gasp, Celestia came. Her cock throbbed and spewed a seemingly endless stream of hot cum into Twilight's deepest recesses. There was no more need to tell Celestia what she wanted – it was pouring into her in surge after gloriously overwhelming surge, filling her already overstuffed womb past all reason.

Either the pulsing of Celestia's pussy or just the endearingly lewd sounds she made must have driven Luna over the edge as well, because Luna followed her sister into orgasm moments later. Twilight's only clues to know this were the way Luna's hooves clutched around her sister's body and the rhythmic gasps Celestia made – not in sync with the throbs of her own cock, but timed in accordance to Luna's bursts of cum inside her.

Twilight's body swelled all over again as Celestia pumped her full with another absurdly oversized load. Her underbelly swelled against Celestia's, both of them growing as they were pumped full and overfull. Just as the excess began to seep out around the base of Celestia's cock, Twilight was filled to the point where the girth strap of her saddle snapped, either end of it slapping down onto the bedsheets now that it could no longer accommodate Twilight's expanding size.

It seemed as if it would never end, as if Celestia would keep pumping into her forever ... Twilight wanted it to go on forever. Just a bit more ... just a bit more...

Just as Celestia's orgasm first began to fade, Twilight's hit her full force, all the more powerful for having been delayed. She fell limp against the bed behind her, but only for a brief moment. Her legs might have been incapable of movement, but her body ... her body danced around Celestia's still-throbbing cock. Her swollen belly heaved up and down as her pussy clenched and milked Celestia's cock from the inside. It seemed like every muscle in her was working hard to get out every last drop Celestia's pale pink cock might be able to pour into her, even if she couldn’t possibly contain it all.

Maybe she even passed out for a short moment ... or maybe it was just a long, very dizzy blink of her eyes. Because when she opened her eyes again, Celestia was still there on top of her, still inside her, looking down at her lovingly. Luna looked down over her shoulder, gazing down with a heady mix of adoration and pride.

Slowly, obviously weary from her exertions, Celestia slid one hoof down along the bed until she reached the obscene mass of Twilight's swollen belly. She traced her hoof up and down the gigantic curve of it. Then she raised her hoof a little and touched her own belly, still enlarged, though not nearly to the extent twilight's had grown. “Oh Twilight...” She took a deep breath, and her cock pumped out its last few drops deep inside. “Thank you. Thank you so much.”

“Thank Luna,” Twilight said, looking up at Luna's face instead. She smiled as she saw – for the first time she could remember – Luna actually blushing.

“Yes...” Celestia gasped a little as Luna slid off her back, pulling out and releasing a small deluge of white to trail down her already white hind legs. “Yes, but it was you who brought this idea to us, Twilight. It was you who brought us together.” She spared a moment to lean down and kiss Twilight's forehead just below her horn before pulling out herself. “Thank you, Twilight. We should have done this ages ago.”

As Celestia pulled out, Twilight lifted her head to look up over the big purple hill of her inflated belly, hoping for one last look at Celestia's magnificent cock and those big pink balls that had just filled her to the brim. She did get one brief glimpse as the excess cum drained out to soak her tail ... but it was truly a last look, because both cock and balls promptly vanished after Celestia pulled out, shimmering into some other plane of existence in the way only magical constructs could, leaving one vaguely wondering if they were ever really there in the first place. Now the only things disturbing the long, supple curve of Celestia's belly were her pert little teats – tiny and pink and entirely ordinary for a mare like her.

As Celestia slid off of Twilight, Luna collapsed onto the bed right next to her. Celestia followed a moment later. Twilight stayed right where she was between the two, lying belly-up. She wasn't even sure she could move, not with her belly like this. Both of the sisters had swollen out until they looked several months pregnant, but Twilight ... Twilight looked like she was overdue for an entire brood. All that churning cum inside her... Had it...?

Twilight's dreamily blinking eyes shot open wide. Had it worked? Was she pregnant?

Even as Celestia and Luna cuddled up on either side of her, Twilight used her magic to pull one of the three pregnancy test crystals over to herself.

That got the other alicorns' attention when they saw it hovering over Twilight’s belly.

“Do you suppose it worked?” Luna asked breathlessly.

Celestia ran one hoof up and down the enormous curve of Twilight's belly. “Oh yes. I have every confidence that our Twilight is about to be a proud new mother.”

Twilight herself, though, was feeling far from sure. She hovered the clear crystal just above her belly, almost afraid to find out. If it turned blue, that would mean her new foal was to be a colt. Pink, a filly. And – the part she dreaded the most – if it turned opaque white, that would mean she was not pregnant at all.

Then again ... if she wasn't pregnant, if by some horrible happenstance it hadn't worked despite all the potions they'd used, well ... they'd probably just try again, wouldn't they? And that had an allure of its own ... or at least it would after she'd had a few weeks to recover from this attempt. With that silver lining in mind, she slowly lowered the crystal down onto her belly, until the pointed tip of it touched.

It flashed, shattered! The little crystal exploded, making all three ponies flinch as shards of it zinged off in two different directions.

Twilight stared at where the crystal had been in gape-mouthed horror. “W-what does that mean? It's not supposed to do that! Should I get one of the backup crystals?”

“No, no... That won't be necessary.” Celestia held up one half of the crystal that had landed on the bed near her. The jagged shard had turned a deep and very prominent blue.

Luna held up the other. It had turned a vivid pink.

Twilight stared up at the two shards as they hovered up above the bed in front of her ... no longer in horror, but still trembling a little. “What does it mean? The pregnancy test enchantment is simple. I cast it myself. This isn't supposed to happen!”

“It did exactly what it was supposed to do,” Luna said. “I invented that enchantment. The crystal split into two shards. That means you are pregnant with two foals. Judging from the colors, one filly and one colt.”

Her eyes going wide, Twilight took the shards into her own magic, drawing them close and then holding them against her chest with her hooves. Two foals? This was more than she'd ever dreamed of. “Oh thank you!” she breathed, at first unsure who she was thanking ... but then she glanced to the magnificent ponies on either side of her on the bed. “Thank you both so much!”

Celestia smiled. “Well, I suppose we won't be needing those backup crystals after all... Congratulations, Twilight. I can't wait to meet your beautiful foals.”

“Actually, Sister...” Luna used her magic to levitate over the other two crystals. She held one over herself and one over Celestia's belly. “I believe it would be prudent of us to make use of the remaining two crystals ourselves...”

“Oh...” Celestia looked down and rubbed the still-swollen curve of her own underbelly. “You're right. You don't suppose ... perhaps...?”

“I would not venture to suppose anything before putting this to the test,” Luna said. Without any further delay, she pressed the point of the crystal lightly against Celestia's belly.

It immediately turned pink. Twilight and Luna gasped, but Celestia only looked to her sister and eagerly said, “Yours next! Do yours!”

Slowly, much more reluctantly than she'd done with her sister's crystal, Luna lowered the last remaining crystal to her own belly. It instantly turned deepest blue, matching the color of her own fur almost perfectly.

“Oh...” Celestia gulped. “Oh my...”

“Indeed,” Luna said, her voice grave. “This is a ... rather unforeseen development.”

“What are we going to tell the nobles? Who's going to take care of our duties while we're busy being mothers? What about our—?”

Twilight pulled Celestia in close to cuddle against her before she could work herself into any more of a panic. By the time she got her hoof around and underneath Luna to pull her close as well, Luna was already on her way and nuzzling herself up against Twilight’s neck.

“I couldn't be happier,” Twilight said, stroking them both comfortingly with her hooves. “My new little foals will have a brother and sister to play with, and I'm happy they'll have an even bigger family. We'll all have a bigger family now. We're all in this together, and I wouldn't have it any other way.”

That seemed to content the two sisters, at least for now. They snuggled up against either side of her, all three swollen bellies pressed up against each other as they held each other close with their hooves.

Soon – very soon – Twilight would need to get up, salvage what she could from Rarity's carefully prepared outfit, and get a desperately needed shower ... but not yet. Not now. Now was the time for warmth and closeness, to hold herself tight against the two mares she'd suddenly tied herself even closer together with. She placed the four crystals – two whole and two shards, two blue and two pink – down next to the three of them on the bedsheet ... where she could turn her head and look at them. She was almost – but not quite – sentimental enough to whisper to them ... but if she had been, she would have told them that they were four very lucky foals, to have the three best mothers anypony could ask for.

Author's Note

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