The Wagered World

“We two are sharing a room?” asked Luna. “I know we are no longer princesses, but surely our demotion is not this precipitous.”

“No, you’re keeping your rooms,” said Umbra. “If I were in Twilight’s place I certainly wouldn’t miss an opportunity to demean the former rulers of the nation I now ruled… but kindness is the tool Twilight favors, and I must say it has a keener edge than I would have imagined.”

“I’m sure Twilight wanted to have your rooms clean when you arrived,” said Chrysalis, “but the cleaning staff had a lot of work this week, and... “ she pushed open the door to the bedroom. It was lavishly outfitted, with purple sheets and curtains the evoked the colors of Equestria’s new queen. “Well, it’s a really nice bedroom, all right? So deal with it.”

“My sister and I aren’t germophobes,” said Celestia, as she stepped inside the bedroom. “We both like our bedrooms, and if they’re not tidy… I think we’ll manage regardless.”

Chrysalis laughed. “Oh, no, that’s not quite the issue,” she said. “Y’see, Twilight sometimes hosts… how should I put this? Theme parties. In your old bedroom.”

Luna, making herself comfortable on the bed, gave Chrysalis a quizzical look. “Theme parties?”

“Yeah,” said Chrysalis. “I was the star of the show, actually! I got so, so good at my Luna impression. Here, I’ll show you.” Green fire raced from her horn down to the soles of her feet, and standing in her place was a double of Princess Luna - only this one was completely nude.

“Thanketh you so much for attending my private lunar gala!” said the double, arching her back to make her breasts bounce. “Now, all of you, please - cummeth upon my tits!”

Celestia’s jaw dropped, and she rubbed at her eyes with both hands, looking between Luna and her doppelganger with an expression of mock bewilderment. The real Luna just rolled her eyes and addressed Umbra. “So my bedchamber, and my sister’s, are… thoroughly coated in cum?”

“Yes,” said Umbra. “The castle’s staff has lots of experience cleaning up huge quantities of cum, but your rooms aren’t ready right at the moment. Anyway… I’m sure the two of you want to pretty yourselves up for our date, so Chrysalis and I will give you some time to yourselves. Chryssi?”

The false Luna turned back into the Changeling Queen, and she and Umbra made their exit.

“So what do you think?” said Celestia, dropping onto the bed beside her sister. “Of all of this? This whole world that Twilight Sparkle has created.”

Luna was silent for a short time, her face unreadable as she considered the question. “It is… far, far more sexual than we would have imagined,” she said. “We would go so far as to call it ‘perverted.’ And yet… we can scarcely dispute that Equestria is better in all the ways that truly matter.”

“Exactly my thinking,” said Celestia. “This, I suppose, is what you get when everyone is free to pursue their desires, freed from limitations. The fact that most ponies have chosen to be mares is something of a surprise, though not an unwelcome one. The larger surprise, to my mind, is how much Twilight herself has embraced and promoted this heightened state of sexuality. I worked closely with her for many years, doing my best to learn everything I could about her… and I would never have guessed that she was concealing such intense and unconventional desires.”

Luna nodded. “I suppose it is always the quiet ones who are the most perverted,” she said. “Do you suppose-”

But as she turned to face her sister, her mouth was stopped by Celestia’s lips - and then her tongue, which probed Luna’s mouth with a voracious energy. Luna was shocked, her eyes wide, but she didn’t pull away - she just let her sister plunder her mouth and exhale hot breaths onto her face and lower her onto the bed. Luna lay there, letting herself be taken by Celestia’s sudden passion, until her sister suddenly broke off the kiss and lifted herself up, leaving Luna prone on the sheets with the ghost of that kiss on her lips. “Tia?” she said softly. “Why…”

“Well, I was just thinking,” said Celestia casually, “that we are surrounded by ponies who are… more accustomed to this world than we are. We need to catch up, Lulu. That means forgetting about the limitations that we once thought bound us. I am sitting next to a beautiful mare with a gorgeous starry mane and a big round butt, and I thought to myself that I should kiss her. After watching you transform… seeing Barb fucking Twilight Sparkle… and, of course, not having sex anytime in the last thousand years… I'm just disgustingly horny. I think it’s time for me to do what I feel like doing.”

Luna’s face slowly cycled through expressions. “We are sisters, though…”

“We are grown mares,” countered Celestia. “And with so many taboos erased, there is no one to tell us we cannot love one another. And let me ask you, sister… why did you not resist?”

Luna was in thought only for a moment this time before coming to her decision. She tackled her sister, pushing her down onto the bed and locking lips with her. Luna seemed intent on outdoing Celestia's kiss, pushing her tongue past her sister’s lips and tackling her onto the bed. Celestia was buried beneath Luna’s body, smothered by her tits, embedded in the mattress by the weight of her giant butt. Even though her butt was magically compressed by her dress, it was still enormously wide and heavy… and as the two sisters embraced, writhing and moaning, that weight pressed down on Celestia’s crotch.

Celestia’s cock, like her sister’s ass, was magically compressed by the dress she wore… but it was still bigger than any pony’s cock had been in the days before Queen Twilight. And now, with Luna’s tongue in her mouth and Luna’s tits pressing against hers, Celestia’s cock was rising, thickening, growing stiff. She gyrated her hips slowly, rubbing her shaft against Luna’s body, delighting in the magnificent sensation of growing bigger, bigger, bigger. She felt her nuts sloshing with seed, her cock growing hot and pulsing with arousal, thick precum shooting in globs from the flared tip. She was ready to go all the way - to tear off her dress, fuck her sister, and bloat that beautiful midnight-blue body with cum.

“Well, that didn’t take long,” said a voice from the far side of the room. The sisters were almost too lost in lovemaking to bother looking up, but the presence of observers in a room they’d assumed was private… well, that was fairly alarming. They pulled themselves apart, standing awkwardly from the bed and turning towards the source of the familiar-sounding voice.

The source of the voice was a pony near the bathroom door, a sky-blue mare with an athletic build and powerful wings folded behind her back. She was bigger than either Celestia or Luna remembered, with a far larger bust and wider hips, though her toned muscles still stood out beneath the skin. But she was still the Rainbow Dash the two of them remembered.

And next to her was another familiar face. Another villain, albeit one reformed for longer than Umbra or Chrysalis had been. Tempest Shadow had received the same upgrades to her curves as Rainbow Dash, but there was a more interesting change as well: underneath a pair of shiny black panties was the irregular bulge of a fat cock and balls, growing and shifting as Tempest developed an erection.

“What are you two doing here?” demanded Celestia, folding her arms self-consciously in front of her chest. She glanced down at her cock, which was prominently tenting her dress, but there wasn’t much hope of hiding it… and besides that, she wasn’t actually ashamed of what she was packing down there. It was damn big, and when its size wasn’t being suppressed it was literally the biggest cock in Equestria.

“Well, we were hoping to run into you,” said Rainbow Dash. She leaned on Tempest, running her hands over the growing bulge in the other mare’s panties.

“You don’t like being watched?” said Tempest, with a thin, confident smile. “ That’s another taboo you should try and push past, girls.”

“And if it’s the incest thing, don’t worry about that,” said Rainbow Dash. “You’re two grown mares, like you were saying. You can make your own choices, and if your choices involve Celestia’s huge cock and Luna’s fat ass, I’m behind you a hundo percent.”

“That’s lovely to hear,” said Luna flatly, not seeming especially comforted. “But why are you in the guest room that was set aside for Celestia and myself?”

“We go where we like,” said Tempest. “And we wanted to meet you upon your return, after you had a chance to speak with our wife.”

“Your wife?” asked Luna, mentally going over the brief list of ponies they’d met since they came back to the castle. It really could be anyone, since ponies could probably have as many wives as they liked in Queen Twilight’s Equestria...

“Aww, she didn't mention us?” asked Tempest. “I guess there was a lot to talk about… anyhow, we’re Twilight’s wives.”

“Yeah, both of us!” said Rainbow Dash, still groping the bulge inside Tempest’s black panties. It was still uncoiling, thick as her arm and well over a foot long. “It was kinda rough going at first… Twilight made this really deep connection with Tempest during the whole Storm King thing, but the two of us really didn't get along at first…”

“Luckily,” said Tempest, “Twilight’s rule ushered in a lot of new ways for people to connect sexually. Now I love Dashie just as much as I love Twilight.”

“Same here,” said Rainbow Dash, giving Tempest’s cock a playful squeeze. “I love myself just as much as I love Twilight!”

“So… both of you?” asked Luna. “How does that work in the, er, bedroom?”

“Well, we’re hardly the first ponies to have three-ways,” said Tempest. “But Rainbow Dash and I have something special we do.” She and Dash shared a smile, meeting each others’ eyes, and then they spoke together: “Why don't we show you?”

Rainbow Dash reached into Tempest’s panties and pulled out her cock, a mouthwatering eighteen inches of purple stallionhood. With another motion of her hand, Dash pulled out Tempest’s fat, dangling nuts and tugged her panties down enough that they dropped to the floor on their down. Then she turned to Luna and Celestia and raised an eyebrow expectantly, ogling the former princesses’ bodies as she handled her lover’s cock.

Luna and Celestia took the hint. The two of them helped the other disrobe - Celestia slipped Luna’s dress off her shoulders and pulled the fabric away from her tits - and when the dress fell away from Luna’s butt, her cheeks ballooned enormously, returning to the colossal proportions that Chrysalis and Umbra enlarged them to. Rainbow Dash and Tempest gasped in awe at the sight of it; it was the biggest ass in Equestria, after all. They’d never seen a butt that big, even in Queen Twilight’s new world.

And Celestia could be equally confident that they’d never seen a cock as big as hers. When her own dress fell away from her body and its magic no longer compressed the size of her cock, Celestia’s shaft sprang forth, fully hard, shooting forward over the marble floor, audibly groaning as it grew to its full length - ten feet long, three feet wide.

“Holy shiiiit,” gasped Rainbow Dash, licking her lips as she beheld the enormous, snow-white shaft. Her eyes caressed its curves and ridges - its colossal girth, its bulging veins, its wide flare and thick medial ring. “How’d you get a cock like that?”

“I suppose Twilight was grateful that Luna and I indulged her little experiment,” said Celestia, waggling her hips so that her enormous tree-trunk dick waved back and forth. “I wanted the biggest cock in Equestria, and my sister wanted the biggest ass… so we got them.”

“Well, that’s pretty cool,” said Rainbow Dash, “but wait til you see what we can do!”

Rainbow Dash drew a breath - and kept on breathing in, much longer than should have been possible. Long after her lungs were full, she continued to inhale… and that air began to fill other parts of her body. Her breasts began to swell, as if the air was filling them… and then her hips started to grow as well, blowing up like balloons as Dash breathed in more and more. She was even growing taller, her body stretching upward, groaning and creaking as she expanded. Her athletic figure grew into a deliciously curvy hourglass, expanding and climbing higher until she was nearly the equal of Princess Luna.

And even then, Dash didn’t stop… but now the excess air was flowing into her stomach, making her belly swell up. She looked as though she was rapidly progressing through a pregnancy, arriving at nine months within seconds… and she kept on growing, her belly growing like a balloon, outgrowing her butt, expanding two feet, three feet, four feet in front of her body. Laughing, Rainbow Dash fell forward, landing on her swollen belly, bouncing a bit before settling on the marble floor. Her stomach continued to grow until nothing else touched the floor but the tips of her toes.

“That’s really something, isn’t it?” said Tempest, stepping forward and lowering the tip of her hard cock so that it was level with Rainbow Dash’s lips. “I just adore the way she grows right before my eyes… but I like this part even more.”

Rainbow Dash opened her mouth, extended her tongue, and took the flare of Tempest’s shaft into her mouth. Dash began to exhale, and her belly began to decrease in size. All that air traveled down the shaft of Tempest’s dick, and it began to fill her up - but not in exactly the same way it had filled up Dash. Like Rainbow Dash, Tempest started to grow taller, but she didn’t gain the same outrageous curves. Instead, her muscles bulged, becoming bigger and more defined. Her breasts and her ass stayed in proportion to her growing body, but her cock and balls expanded much faster than the rest of her. Her whole body creaking and groaning with growth, her thick purple cock swelled and lengthened. It grew by inches, then by feet, forcing Tempest to slowly walk backwards. Her purple nutsack grew past her knees, then landed on the marble at her feet, making her gasp slightly as she felt the cold on her skin.

Rainbow Dash emptied all the air in her belly, until she lay tits-down on the floor. And Tempest, thanks to her gift of breath, was almost as monumentally endowed as Celestia herself. Her nuts were every bit as big, and her cock, at nine feet, was just a foot shy of the former princess’.

“That’s what we call a ‘blowjob’ around here,” said Tempest, stroking the base of her giant cock with both hands. “But, uh, we still do the regular kind of blowjobs, if that’s more your thing.”

“We got rubber bodies!” said Rainbow Dash proudly, as she stood up from the floor. “Well, sort of. We wanted to be stretchy and inflatable, and Twilight and Tempest sorta figured out how to make the magic part happen. Stretchy skin that works like a balloon… there’s tons of fun stuff we can do with bodies like these!”

“And we aren’t the only ones who’ve been growing,” said Tempest, waggling her finger in the sisters’ direction.

Celestia and Luna’s eyes had been glued to Dash and Tempest’s erotic inflation, but now they looked at each other and down at themselves. They hadn’t realized it at the time, but now there was no denying it - they were both bigger.

“Looks like you both picked up about six inches of height,” said Tempest, squinting as she evaluated them. “And corresponding growth in your busts… And big gains in Luna’s big fat ass and Celestia’s monster of a cock.” Tempest took a couple steps, moving with ease and grace despite her dragging balls and her nine-foot-long penis, and nudged the head of Celestia’s cock with the tip of hers. “It can be a little odd, growing that way,” she said. “It feels like becoming aroused, but a great deal more intense… I’m sure you’ll get used to it, though. And you’ll definitely come to enjoy it.”

“I imagine that we will,” said Luna. “And sister, there’s no reason to let those two have all the fun with their wonderful bodies when the two of us are even bigger.” She straddled her sister’s cock, facing away from her - which put her tremendous ass right in Celestia’s face. “I have to say, I’ve had quite enough of just looking at your big, beautiful cock,” said Luna. “I am ready to do something to it.”

Luna lay herself face-down on top of Celestia’s cock, nestling the thick shaft between her tits. A three-foot-wide cock would make a boobjob impossible for most ponies, but Luna was no ordinary mare. Her cleavage was big enough to engulf her sister’s shaft, and once she had that giant cock between her pillowy blue tits, she began to rock back and forth. Celestia groaned in bliss as Luna’s tits pleasured her cock - and on top of the boobjob, she also had her sister’s colossal rump bobbing up and down in her face. She stretched her arms out, letting her hands sink into the soft, jiggling flesh, and joyously groped the world’s widest butt.

“Ahh, Luna,” sighed Celestia, “This is… heavenly… Oh my stars, this is absolutely worth losing the throne of Equestria.”

“I am inclined to agree,” said Luna. “Without Queen Twilight, you would never have a cock taller than your body… and your sister would not have tits big enough to embrace it. I am not even the one being pleasured, and I am still enjoying this greatly… it seems my breasts are powerful erogenous zones… And if I am being candid, Tia, I must admit that I have dreamed of doing just this sort of thing with you.”

“And I’ve dreamed of having a cock,” Celestia admitted. “Never one this big, even my wildest dreams. But you were always in those dreams, and I always woke up quite wet…” Her cock bucked, making Luna’s whole body jiggle. “Ahh, it won’t be long before I cum,” groaned Celestia. “Oh Luna, I can tell it’s going to be so big…” Her tip was already oozing precum, spilling a half-gallon of spunk with each gentle throb of the giant shaft.

“You know, we’re not actually done,” said Rainbow Dash, taking a seat on an unoccupied portion of Celestia’s dick. “Trust me, it’s worth the wait. Let us do our thing, and you’ll be shooting a way bigger load when you finally get your rocks off.”

“Well, I am certainly curious,” said Luna, slowing the pace of her titjob. “Sister?”

“Oh, all right,” groaned Celestia. “But don’t stop, Luna. Equestria’s largest cock can only wait so long...”

“All right, then!” said Rainbow Dash, placing her hands on Tempest’s flare. You ready to blow their minds and their loads?”

Tempest smiled. “You know it, love.”

Before the curious eyes of the two sisters, Rainbow Dash crouched and pressed her face up against the head of Tempest’s cock. At first, it seemed that she was merely going in for a kiss… but after her lips met Tempest’s huge slit, she kept on going. She sank her face into the hole, then her entire head. She paused there, neck-deep in Tempest’s cock, and Celestia was just about to ask what she was doing… when Tempest’s dick made a loud wet slurp and began to suck Dash’s body further inside.

“Ahh, yeah, get in there, Dashie,” groaned Tempest, as her cock engulfed Rainbow Dash’s shoulders. “Let my big cock just swallow you up…”

“What are you doing?” asked Luna, tilting her head as she kept up her boobjob. “I think perhaps I like it, but… I am not sure what I am seeing.”

“It’s exactly what it looks like,” said Tempest. “I'm… eating Rainbow Dash with my cock. It's, uh… oooh…” She paused to moan and shudder as her cock widened to swallow up Dash’s tits. The big purple cockhead bulged hugely, slurping its way around Dash’s huge bust, and Tempest sighed with satisfaction she swallowed Dash up to her slim belly. “It’s just step one…”

Tempest moaned and clutched herself as her shaft widened to swallow up Rainbow Dash’s enlarged bottom. Her ass was a great deal wider than her bust, forcing Tempest’s cock to grow much bigger in order to swallow it. The shaft bulged with the shape of Rainbow Dash’s wriggled curves, slowly sinking towards Tempest’s body - and then, when her ass was completely swallowed up, the rest of her disappeared almost instantly with a sudden slurp. Her curves slithered down Tempest’s shaft - and when it reached the base of her cock, her purple balls rapidly swelled, doubling in size as they absorbed Dash’s body.

“What… what just happened to Rainbow Dash?” asked Celestia, breathless from the ongoing boobjob and the strangely arousing sights in front of her.

“I just swallowed Dashie up,” said Tempest, “and now she’s a big blue load of living cum, deep in my big fat nuts…” She dug both hands underneath her dick and lifted it towards her face. It was still soft, somehow, and she was able to bend it towards her mouth… and then shove it past her lips, into her wide, yawning mouth. Letting out a long, muffled moan, she fed her long, thick cock into her mouth and down her throat, where it bulged prominently from her belly.

“Such a strange display,” groaned Celestia, her face half buried in her sister’s wobbling asscheeks, “but it’s… fucking hot…” Her cock trembled between Luna’s tits, and she heard a thick sloshing from within - then, with a jolt, the immense shaft began to spray cum like a firehose, shooting thick white cum across the room and splattering the far wall with a dripping layer of spunk. Moaning, her cock bucking under Luna’s body, she fired off load after load, coating more and more of the walls and the floor. Celestia’s cock started to rise, effortlessly lifting the weight of Luna’s body, and began to shoot cum unpredictably, firing loads of spunk that arced towards the ceiling and coated everything in the room. The bed, the dresser, and the marble floor disappeared under a shower of cum, leaving everyone up to their ankles in jizz.

“Celestia!” said Luna, once the cock underneath her stopped spurting. She leaned her head down to lick some cum off the veiny shaft she was riding. The taste was divine, rich and salty and sweet, and she swallowed it down hungrily. “That was so… powerful… I see now why our bedchambers needed such a thorough cleaning.”

“No, that was… just precum,” Celestia groaned. “I can feel so much more, still inside me…”

“Are you serious?” gaped Luna. “I suppose I must keep working to make you cum, sister…”

The knowledge that Celestia was holding in an even bigger load also seemed to have an effect of Tempest. Her cock, still deep in her belly, trembled with arousal and then began to chug, pumping a huge load into Tempest’s gut. Her stomach started to swell, bloating much the same way that Rainbow Dash’s had… but she was filling herself with thick cum, living cum, a liquid that used to be Rainbow Dash. The vast majority of it stayed inside her, but a few trickles of fluid escaped her lips; the fluid, Luna and Celestia couldn’t help but notice, was a liquid rainbow, dripping down Tempest’s chin in a play of vibrant, shifting colors.

But before it could drip too far down, purple light began to erupt from her body. Blinding light coated her skin, turning Tempest into a radiant body too bright to see clearly. When the light faded, someone new stood in Tempest’s place. Someone big - a navy-blue mare who towered over the sisters at eighteen feet tall. A mare with a messy mohawk that looked like a dark rainbow, with powerful wings and a long - but still broken - horn on her forehead.

This new mare - this alicorn - was an awe-inspiring amazon. She was Celestia’s superior in every sense - bigger muscles, a thicker ass, and rounder tits. And her stallionhood was godlike, so long that its girthy, veined length coiled on the floor. Her nuts dragged on the floor, audibly churning with spunk as she looked down at Luna and Celestia.

“Oh.. oh my… what just happened?” asked Luna, staring disbelievingly at the giantess in their midst. “Who are you?”

“I’m pretty much what I look like!” said the alicorn, flipping her mohawk in Luna’s direction. “Half Rainbow Dash and half Tempest Shadow. I call myself Fast Temptation, but you can call me your big-dicked sex goddess.”

“You are... breathtaking,” sighed Celestia. “I think… I think I can feel myself growing again…”

“Yeah, it’s a unique feeling, huh?” said Temptation. “You see a mare like me, and your body wants to rise to the challenge… and that means getting big.”

Celestia’s body groaned with expansion, muscles creaking and balls sloshing as she grew. Her body stretched in every direction, spreading across the floor, sending ripples through the pooled cum. Her cock extended and thickened, veins bulging and pre shooting across the room.

Luna, still riding her sister’s swelling cock, also surged with growth. Like Celestia, she grew taller - but her colossal tits and immense ass grew even faster than the rest of her, ballooning rapidly as arousal coursed through her. She was holding onto Celestia’s cock, trying to ride it… but her growing body was unwieldy, and she slipped off, landing on her huge butt in the warm cum that coated the floor.

“Wow, I’m impressed,” said Temptation. She stroked her long blue shaft, and it writhed lasciviously as it uncoiled and rose from the floor. “The only reason I’m this big is that I’m two ponies. Not every pony can grow like that.”

Celestia now stood at seventeen feet, nearly the same height as Fast Temptation - and although she didn’t quite have Temptation’s amazonian musculature, she did have a cock of equal size. Luna was just as tall as Celestia, but she was face-down on the floor, pinned down by the weight of her curvaceous assets. “Ah, this is… impractical,” said Luna, swinging her arms and legs fruitlessly. “I’ve been immobilized by the greatness of my own body.”

“Oh dear,” said Celestia. “You’re helpless, sister.” She laid her hands on Luna’s ample bottom, groping her deep blue flanks and making her sister moan in blissful anguish. “A pony could just stroll right up and take advantage of you, and you’d just have to lie there and enjoy it…” She slid her cock into the crack of Luna’s ass, sliding it a couple feet deep into her bottom.

“Hmm, maybe being immobile isn’t so bad,” said Luna. “As long as there’s some hugely endowed mares to make sure I do not grow bored…”

“Looks like your sister’s got your pussy covered,” said Temptation, stepping forward with her navy-blue cock at full attention. “How about I fill your mouth?”

“That sounds magnificent,” said Luna, licking her lips and wiggling her rump. “I am powerfully worked up, and I badly need to be filled by the biggest, meatiest cocks I can find… and I want to feel what it’s like to be filled with a big, hot, sloshing load of cum, just like Twilight’s dragon girl…”

“You’re getting two loads, sister,” said Celestia, penetrating deep into Luna’s giant bubble butt and searching for the lips of her pussy. “And you’re getting them from bigger mares with longer cocks and much bigger nuts…”

“You’re going to be big, Luna,” said Temptation, teasing Luna’s mouth with the oozing tip of her cock. “Me and your sister are gonna shoot such big fuckin’ loads inside you, gonna fill you up bigger than any pony’s ever been…” She thrust her cock into Luna’s mouth, easily sliding the first three feet of her cock into her throat. Luna’s body accepted her immense girth easily; Chrysalis and Umbra’s magic had made her a creature capable of accepting any cock imaginable.

“I cannot wait to shoot my very first load,” sighed Celestia, as she slid her cock into her sister’s dripping pussy. “You saw how much pre I shot, and even that was such a glorious, blissful release… when I cum, it’s going to be absolutely heavenly… and I imagine your body is capable of just as much pleasure. I can’t wait to make you cum, Lulu…”

Temptation pushed her hips forward gradually, until the tip of her cock bumped up against Celestia’s. “Okay, there’s not quite enough room in your sister for both of us,” she said, “So we’re gonna need to fuck her with a rhythm, you get me? Try to keep up.” She pulled back, giving Celestia space to thrust - then, before Luna’s moans of pleasure could escape her mouth, Temptation thrust her cock down Luna’s throat, filling the space left behind when Celestia pulled out.

“Okay, lemme take the lead,” said Temptation. “A little faster every time we thrust… and soon we’ll be giving your sister the fucking of a lifetime.”

Celestia, though she’d never fucked anyone with a cock before - much less the biggest cock in Equestria - had a solid sense of rhythm and a natural grace, even in her new body. She followed Temptation’s lead expertly, going in when Temptation’s cock went out… and her body sang with pleasure as her long pearly-white cock slid in and out of Luna’s slick, tight pussy. “Luna,” she grunted, “It feels so good to fuck you, Luna. I never imagined anything could feel this good, but now that I am balls-deep in my sister’s tight pussy, I am… simply in heaven… Ohh, and Luna, this ass, this big, soft, delicious ass… you’ve grown so big, Luna, and you’ve never looked hotter…”

“You’re really losing yourself in this, ain’tcha?” laughed Temptation, her navy-blue nuts smacking against Luna’s chin as she thrust faster and harder into her mouth. “I guess I can’t blame you, since you’re a first-timer. Plus, your sister’s a great fuck. Second tightest mouth I’ve ever pounded, so I can’t imagine how good her cunt is.”

“The second?” gasped Celestia, meeting Temptation’s eyes. “Who is… the first?”

“Who else?” said Temptation. “My wife. The queen. Twilight loves to get fucked, and she’s always perfectly tight.”

“Yes, of course,” said Celestia. “I imagine Queen Twilight is looking forward to taking her turn with both of us… I imagine she wouldn’t grant us Equestria’s biggest cock… and its biggest ass… and not want to try them out.”

“Oh, she definitely wants to fuck her old mentor,” said Temptation, with a devious grin. “I don’t think that’s a secret. She’s wanted that since long before she was queen.”

Celestia lost herself, for a time, in the rhythm of sexual congress, trading turns with Fast Temptation as the two of them filled her sister with cock. After a while, her mind swam to the surface of her sexual reverie, and she met Temptation’s eyes. “Temptation?” she asked. “How long… does it usually take to cum? I keep getting more and more aroused… more tension in my cock and more sloshing weight in my balls… I feel like I’ve been fucking forever, and it feels great, but…”

“Heh heh, ponies like us are built for long fuck sessions,” said Temptation. “You know we’ve been going for like an hour already?”

“An hour?” said Celestia incredulously. “I don’t seem to have much of a sense of time…”

“Yeah, that’s happened to me too,” said Temptation. “Anyway, if you’re like me, you’re not even close to done. A cock like yours needs to fuck a tight pussy for hours before you can really cum. But trust me, babe, it’ll be so worth it.”

After that, Celestia’s mind dropped back into the senseless sea of bliss, and for two timeless hours there was nothing but the tightness of Luna’s slick, hot pussy and the meaty slap of Celestia’s fat white nutsack against Luna’s asscheeks. Then, after an eternity of pleasure, something changed inside Celestia; the tension in her cock, which had been rising and rising all this time… finally overflowed. With a sound like a violent, sudden storm, Celestia’s nuts sloshed and pumped the first immense gush of her hot, thick load.

Fast Temptation felt the flow of cum sloshing inside Luna, filling her body, and that sent her over the edge. With her cockhead pointed straight down Luna’s throat, she released her load, sending gallons upon gallons rushing into the other mare’s belly. And Luna - who had been going through the same unceasing rise in sexual tension as the other two mares - finally came as well, her pussy clenching mightily around her sister’s pulsing shaft.

Two minutes into her orgasm, Celestia wanted to ask Temptation just how long this was going to last… but she couldn’t find her voice, couldn’t use her mouth for anything but a series of wordless moans. Over and over, her cock pumped what felt like entire lakes of hot alicorn cream into Luna’s hungry pussy. And Luna was growing, swelling, ballooning with cum as she was filled from both ends.

After five minutes passed, Temptation slumped against the cum-bloated surface of Luna’s body, gasping for breath and purple-faced. “Holy shit, Celestia, are you still going?” she asked. “I thought my loads were massive! Damn, I wanna see how much you can fill your sister’s pussy. Go, girl, go!”

Still voiceless from the intensity of her orgasm, Celestia pumped her hips and dug her fingers into her sister’s pillowy bottom, shooting a ceaseless flood of thick spunk into her pussy. With every hundred-gallon spurt, Luna swelled bigger and bigger; her tits, ass, and belly got rounder and sloshier, spreading across the generous width of the guest room. She was increasingly a cum-balloon, her limbs and her head dwarfed into insignificance by her bloated curves.

Ten minutes into Celestia’s orgasm, Luna felt the walls of the guest room against her skin. All of the walls, the entire circumference of the room, was touching her - and her sister’s cock was still full-force pumping its hot load into her pussy. Her body still needed to expand, so it went upward, climbing toward the domed ceiling, progressively taking up more and more of the dwindling space in the expansive room. Luna felt Fast Temptation’s cock sliding out of her, making a pop as it cleared her lips, and she struggled to speak - although, like her sister, Luna herself was still in the midst of a colossal climax.

“Celestia,” she groaned, “Sister… fill me, make me bigger, I want to fill this room, I want to be a beautiful blob filled with your hot… white… cum…” More spunk, a rushing river of the wonderful stuff, flowed from Celestia’s slit, and Luna felt herself bloating even bigger, her immense ass and huge pillowy tits compressed against the wall as her body rose ever higher. She felt her wings touch the ceiling, and expected to burst through the walls at any moment…

And then the flow of cum slowed to a trickle - just a few gallons oozing from the tip - and then it stopped. “Fifteen minutes!” said Temptation. “Holy shit, Celestia, not fucking bad! I gotta tell Twilight about this!”

“Yes, I’m sure she’d… love to hear it,” said Celestia, her amazonian body pinned against the wall by Luna’s sloshing bulk. “But until Luna… recovers… I don’t think I can make my way out of this room.”

“Yeah, she’ll shrink in a bit,” said Temptation - who couldn’t see Celestia, as they were on opposite sides of Luna’s massively swollen body. “But for the moment, you’re probably stuck where you are. Me, though, I’m pretty close to the door… and it’ll be easier to wriggle out of here if I unfuse…”

Temptation’s body was engulfed in light, and when it cleared, two ponies wriggled their way down to the cum-splattered floor and edged towards the door that led out to the hallway. Once they’d freed themselves, Rainbow Dash and Tempest Shadow spent a moment fixing each other’s mussed hair and kicking the jizz off their feet.

“That was fun,” said Dash. “Awesome to have the princesses back, huh?”

“Absolutely,” said Tempest. “It might be a little while before anyone else can play with them, though… someone should tell Umbra and Chrysalis that they might be late to their double date.”