Author's Note

The gurls get up to even more cock sucking fun, while the Twilights' get a lot closer than either thought possible.

Twincest is Wincest

The gurls all watched as Sunset Shimmer worked Arthur’s incredible cock. Her fingers playing across the veins that covered his cock like she was playing a flute, drawing a low, masculine moan from the man.

The two moved together in harmony and every gurl present felt themselves getting wetter just watching Sunset Shimmer work. Every movement, every flex of muscle and dance of cock and tit a sensuous, sumptuous feast for the eyes. Rarity and Fluttershy started leaking milk in sympathy, just a few drops but it was there. Applejack as the only other milker in the room would have leaked, if Rainbow Dash hadn’t flashed across the room to her orange tits in a flash and begun sucking on the nips so quickly it seemed like she was sucking both at the same time.

For Sunset and Arthur though, the rest of the meeting room faded away, Arthur’s whole world was just orange tits, cock, and Sunset’s eyes as she looked up from his cock to blushingly meet his own eyes, and her whole world was just his cock between her tits, and between her lips.

All the other gurls gasped aloud when in a sudden burst, Arthur came and Sunset began to greedily gulping the first load before starting immediately returning to sucking his cock, even as she began flexing and growing, earning a cheer from the crowd as the other gurls all snuggled a little closer, powerful muscles flexing and fingers caressing heavy tits as they all watched.

Even as she sucked and worked Arthur’s cock, her arms pumped bigger, flexing larger and larger, her tits gaining more veins and nearly doubling in size as her abs gave a burst and became so well defined you could shred cheese on them. She had to readjust her stance, and Rarity gave a low orgasm of applause, as Sunset Shimmer rose above the table, becoming even taller in horse body than Princess Twilight was, her horn taking on it’s own orange glow despite no magic being in use. She kept flexing her arms, smiling around Arthur’s cock at how Arthur’s manhood throbbed in sympathy seeming to grow with each of her own growing flexes.

But despite how all the gurls were enjoying the blowjob titfuck and growth, Princess Twilight was frowning and had turned her head to her nearly-twin-glasses-wearing counterpart. “Twilight?”

“Y-yes, your ladyship?”

Princess Twilight blinked before grinning and giving the other Twilight a hug, her massive arms wrapping around the smaller woman, Twilight’s own matching her a second later in a powerful hug. “Just Twi is fine.”

“S-same.”

“Well, Twi, umm… I’m concerned about Sunset Shimmer and her... sudden cum guzzling.” Princess Twilight glanced back to the orange unicorn, her eyes going wide “She’s my friend too but… she hasn’t previously handled… having too much power well. And she’s still going. I fear she might intend to drain Arthur, and none of us have managed that yet, even working together. She could end up bigger than the entire castle!”

Twilight felt an echo of herself, and of Midnight Sparkle, her super strong, super muscled, and super self-centered alter-ego that nearly consumed her, and she wanted desperately to save Sunset Shimmer from anything, even herself. “How can I help?”

“I think I have an idea, using your science brain and my magic brain together, but just in case…” Princess Twilight turned and shouted, “SPIKE! Meet me and Twilight in the mirror room in five minutes.”

“Uh, sure, Twilight,” Spike said, distractedly staring and stroking his own dragon cock, his own muscles flexing as he leaked flaming precum watching Sunset Shimmer swallow her second load and surpassing even the Twi-twins in size. “Be… right… uh… there…”

“And hold back on too much of that.” Princess Twilight added, noting the cum. “We might need that. In fact…” With a surge of magical power, a cockring appeared around the base of Spike’s multiridged dick, holding the cum inside of those balls, “I’m sure we will.”

~

When Spike came into the room Sci-Twi and Sunset had entered their world from, he found the ‘great mirror machine’ as he oft thought of it, in a general sense of disarray. In the middle of the room, working on the various bits with all four hands, was Twilight Sparkle times two. It took Spike a moment to divert enough blood away from his cock… the sight was just too cock-hardeningly good, to really sort out what he was seeing.

The two Twilights, Glasses-yes-wings-no and Princess Twilight or…. Sci-Twi and Pri-Twi as Spike decided to shorten it, were working together so closely they seemed to almost be using all four arms without asking each other what they needed, and instead were talking a mile a minute about dimensional physics, one from a science standpoint the other from a magic standpoint.

Either was over Spike’s head, but both? That just made his head spin, and not in that fun-way like when one of the gurls gave him a good blowjob. “Uh girls, everything ok?”

“Oh of course, Spike!” They said in echoed unison. “We’ve got this sorted and almost…. Done!”

The whole thing suddenly gave a purple glow and pulled together, even as Sci and Pri-Twi stepped apart, grinning at each other. Their muscles were pumped from the work and their breasts rose and fell in unison as they puffed hard from restoring and rebuilding a dimensional traversing magical machine.

The fact that they were breathing so hard that their massive breasts actually bounced against each other with each puff, despite the fact that their heads were feet apart, did nothing to divert the blood flow from Spike’s cock. “Uh, so what did you do?”

“Oh Spike, we just said what.” The two rolled their eyes but grinned at each other.

“Ok so… what do you need me for?”

“Basically, we’re worried about how fast Sunset Shimmer is growing and we’re going to need your cum to keep up.”

“But there’s two of us, and only one Spike cock.”

Spike frowned. “We’re not doing the dual cock thing again. That was... too much for me.”

“Oh don’t worry, we’ll keep you to one, and we’ll need our mouths to drain Sunset so we’ll need you to put it directly into our womb.”

“So we’re going to use the dimensional portal to partially fuse so we have one pussy for you to fuck us both with!” The last part was said in unison as they grinned at each other, before Sci-Twi’s face somewhat fell.

“I never thought my first time would be with my lower half turned into a horse, with a male dragon, and while sharing a body with my alternate dimensional self.” Blushing, Sci-Twi looked to Princess Twilight and saw the mirrored smile and blush upon her semi-divine countenance.

Princess Twilight shrugged but leaned forward and gave Sci-Twi a kiss, muzzle to muzzle. “Don’t worry, Twilight. Your first time should always be memorable and what could possibly be more memorable than sharing it with someone special, literally?”

Sci-Twi rolled her eyes but smiled, reaching out to give the bustier woman’s breasts a squeeze with both powerful hands. “I don’t think that is what’s going to make this memorable, but let’s do this!”

Spike bit his lip, watching the two gurls, one Unicorn, one Alicorn, step into the mirror together and squeal in orgasm as they were sucked into the other dimension.

~

Stepping out the other side of the mirror into the front of Equestria High, Twilight blinked and adjusted her glasses before glancing to her right at the blushing woman sharing her shoulders. Thinking quickly, Sci-Twi pulled out her phone and just like Rarity had taught her, shot the perfect selfie, lips pursed included. Pulling the phone back to herself and holding it such that both she and her… partner could see, they checked out what their new form looked like in her world.

They were sharing a pair of incredibly long, insanely well-built legs, barely contained within the tiny purple skirt that struggled to contain their wide hips. They could tell that they were ‘going commando’ from the slight breeze the caressed the firm butt cheeks that they could feel were slightly on display.

From their tightly built waist two sets of abs sprung up, spreading into two fully separate torsos, each having two of the most powerful arms in the world, arms bigger than what she estimated their separate legs would be. Their breasts, despite being smaller than in the poni-gurl world, were still at least as proportionately bigger from when Sci-Twi had first stepped into that other world.

What really surprised her was how much leaner and stronger their faces looked as 'Equestria Gurls’ than the last time she’d been one, and the obvious differences and similarities the two women had now that they had a bone structure her mind was more used to parsing. We really look more like twins than the same person, don’t we? Sci-Twi theorized. Maybe that should be conjoined twins…

“Well I’d say that was a success.” Pri-Twi nodded to herself, noting how their ‘smaller’ breasts were nearly bursting out of their tight blouses in a way that she wasn’t sure if Rarity of either world would approve or reject. She did think that Sci-Twi looked quite comely nearly ripping through her shirt with just her powerful tits, a tingle in their shared pussy letting her know that Sci-Twi probably felt the same about her own orbs. “Ok, shall we head back and see if we can save our friend?”

“Wait, there’s something I want to try first!” Sci-Twi paused their turn towards the portal to reach up and grasp her necklace with the hand on Pri-Twi’s side. “Ponnnnnyyyy-UP!”

Pri-Twi was about to inquire on if it was Rainbow Dash or Pinkie who’d come up with that saying when she felt the magic of friendship flow through her… them… both? Both.

As the glow faded away, the two women stared in shock at their combined body. They were over sixteen feet tall, with breasts larger than even their pony-gurl forms. They flexed their arms, both women looking to their closest bicep in open mouth shock before turning back to each other with huge grins.

“How about we go back through the portal super charged like this?” Pri-Twi presented. “Could be an interesting experiment to see how this translates in the other universe.”

“I’m game if you are.” Sci-Twi bit her lip, and just as they were stepping back through the portal, pulled her twin into a kiss, using all the strength she could, knowing she wanted at least one really deep, pussy wetting kiss with this woman while like this before they went to the other world.

Pri-Twi was surprised but quickly met it with just as much fervor, the two women squeezing each other tight with their four powerful arms and mashing their heavy breasts together. They went to fall to the ground and continue their mutual pawing, instead falling into the mirror portal together, squealing into each other’s tight, strong lips, around each other’s exploring tongues in the sudden orgasm that filled their shared pussy.

~

“Oh… my… huh?”

“Uh, Twi?” Spike reached out and hesitantly touched his friend’s shoulder as the poni-princess came back to herself. “You ok?”

“Of course, Spike, why wouldn’t I be?” She pulled herself to her full, insane height, legs bigger and thicker than an entire pack of Clydesdales, her doubled spiral horn thrusting to the ceiling so fast and hard, Spike was unsurprised when it actually pierced it, forcing the poni-gurl to duck her head slightly as she stretched her incredible arms, twice as big and thick as Princess Twilight had been earlier. And the breasts…

The breasts were like the rising sun, a sight to behold and yet so grand, so wonderful, that Spike wasn’t sure if he wanted to keep staring, or look away. “But… what about… ummm… there being two of you?”

“Oh, don’t worry.” The large woman smiled, reaching up to absently adjust her glasses before reaching further up and readjusting her crown. “We’re both in here. Our brain is kind of a Venn diagram at the moment, with 90% overlap, and 5% Princess and 5% Equestria gurl. I guess I… or we? We must have miscalculated a bit, or maybe Sci-Twi and Pri-Twi were more mentally alike than we initially realized. Could have been that shared orgasm as we fell through the mirror too.”

Spike swallowed hard as the incredibly powerful woman leaned forward, her breasts so firm they didn’t even jiggle, but first underboob, then full boob filled his vision before Twin-Twi’s face filled his view. “And now, it’s time for that wonderful cock of yours to fuck this gurl nice and hard.”

~

As a glow that hardly anyone noticed to Spike’s eyes fade, across the kingdom a similar glow faded from Princess Celestia’s eyes and she turned and called out to Luna, awakening her sister, Princess of the Night.

The dark furred little sister stepped into the room, her massive moon sized tits (or so many of their followers whispered to each other) entering the room far before the yawning princess did. “What is it, sister?”

“Lulu, I’m afraid we may have to intervene with my favorite gurls.”

“But Tia, you said we shouldn’t intervene with what they’re doing, that they may find the secret of-”

“Not only must we intervene, Lulu, we may need the help of… Celestial Eclipse.”

Luna gasped, but felt her heavy tits churn, and nipples sprang to instant hardness as her grand orbs inflated with milk at the thought of their ultimate form.

~

It hadn’t quite been true, what Dual-Twi had told Spike. Her brain wasn’t a Venn Diagram, per se, it was more like there were simply both Twilight’s talking, in unison, and mostly saying the same thing. They were mentally what Princess Twilight had been hoping for physically, a single body with both heads, mentally speaking. Twilight’s personalities separate and equal. But then, he was a boy dragon after all.

Instead, Twin-Twi, as she thought of herself, turned her attention to the fit young winged gurl who’d just darted into the room.

“W-woah. What happened to you?”

“Never mind that, Rainbow Dash. What’s going on in the table room?”

“Oh, uh, Sunset Shimmer just got Male-Arthur to swallow another load of milk and I think she’s about to start growing again before going in for thirds on a cum blast, and I wanted to check and see if… well, you guys wanted to see, because I’m sure it’ll be one of the most awesome things since Luna had that dream that all of us were growing huge tits and-”

“Made us all have an orgy, I remember.” Twin-Twi blushed as internally Pri-Twi shared the memory with Sci-Twi, both women briefly shocked as sharing the memory made it like Sci-Twi had been there engaging in some big titted lesbian horse action in the dream plane along with her Princess Twilight and the others. “Ok, so we need to hurry!”

“Yeah! You don’t want to miss this!”

No, we really don’t. The two Twi’s looked to each other mentally, biting a lip before they had to teleport through the doorway, as there was no way she could fit anymore at her new size. Spike, the last one out of the room, gave a whimper as he glanced down at his heavy, full balls.

~

The Trio rounded the corner into the ‘table room’ just as Sunset Shimmer gave one final swallow and moaned as Arthur’s cock popped free from her lips.

Sitting him aside, she reached down with one hand to caress her incredibly well filled belly. Moaning aloud again, she felt the cum begin to be absorbed into her, first in her legs, the four hooved appendages, not just her clompers but her whole legs groaning as they grew more powerful and thicker, surpassing all but Twin-Twi’s mega legs, hinting at what was to come.

Her hugely inflated belly gurgled and shrunk, but not from absorbing more cum, but from her belly becoming more powerful, tighter, stronger, able to better squeeze that cum filled contents, veins rippling up across her surface as her full horse body seemed to inflate larger and stronger than anyone else in the room, and rising her orange human-ish torso up higher.

She sighed briefly, a slight shiver passing up her spine before she took in a full breath. With a mighty yell, she flexed again, her breasts seeming to leap forward on her chest, expanding faster and stronger than any other breasts, more than any of the five girls at her feet… well four, and a nearby fluttering Rainbow Dash, combined, before growing AGAIN, growing much larger than Sci-Twi and Pri-Twi had before their fusion.

Sunset caressed her orbs as her muscles rippled across her back, and down her arms, until her hands were finally strong enough to ALMOST dent her firm, vein covered tits. She yelled in success as the main five cheered along. AJ gave a few whoops, mixed with Pinkie Pie’s cheerleader-esque cheers. Rainbow Dash zipped loops around the large Unicorn Gurl, her fingers and feathers tracing enticing lines across the incredible bumps, ridges and curves of Shimmer.

Twin-Twi had to admit, the gurl looked good! Sunset Shimmer was a study in bronze of everything the gurl form could be, proportionately as large of tit as Princess Luna.

No. Wait, those wonderful, dense tits are proportionately at least 14% bigger than mine, possibly 20%. Sci-Twi’s mathematical circumference measuring inserted into their thought process while calculating the head-to-tit ratio and comparing it with her own.

But then, eveyrone’s eyes fell to Arthur, his heavy moans pulling every gurl’s attention, their pussies twitching in response before they spotted the source of his distress.

His balls were nearly the size of Celestia’s Tits!

“Celestia’s Tits those balls are big!” Rainbow Dash bluntly said, unknowingly using one of her favorite curses in reference to both the situation and the size of those balls.

“So… big…” Twin-Twi sighed, her hand feeling up one of her massive tits.

“Looks like I’ve got a bit of growing to do to catch up to you, Twi.” Sunset said, acknowledging the other woman, the fused woman, for the first time. “Arthur here just had his fill from my tits, and I can’t wait to see what a third load of cum from him does!”

Using her new muscles, she scooped up Arthur, actually having to flex her magical power to enhance even her own powerful arms to really lift the massive balls. Cupping them in both hands, she hungrily took his cock into her muzzle, sucking him deep down her throat, and using her lungs to put the most intense suction she could, delighting at the instant reward of pre-cum, making her nipples pearl with milk.

Milk that the mere scent of was like an aphrodisiac for all involved.

Twin-Twi gasped as she saw Sunset set Arthur down on her own tits, by the balls. Her hands caressing all over the huge, heavy balls. Seeing where this was going, Twin-Twi poured all the magic she could into it, and teleported them all outside…

~

With a loud puff of magical smoke, all seven girls reappeared outside, Twin-Twi flexing her muscles hard at the magic that had coursed through her fused body to be able to transport that much gurl in one go.

“I didn’t know you could do that.” AJ blinked, checking herself over. Once she’d been teleported with Princess Twilight and had... a bit of an accident. Being a pegasus had been fun, but Rainbow Dash had quickly wanted the wings back.

“I didn’t either!” Twin-Twi caressed the side of one tit, still puffing a bit. “Just glad to get us all outside before-”

“WOOO!” Pinkie shouted, crushing her tits to her chest as she shouted, her powerful arms nearly exploding in muscles with the effort, her veins pumping in a massive ripple along with her speedy heartbeat. “Suck that DICK!”

All eyes turned to Sunset shimmer as she did an admiral job of holding her breath, deep throating the massive schlong of Arthur, his cock visibly bulging her throat, the veins that crisscrossed that dick standing out even through her neck. Her powerful hands clutched his balls, her arms bulging obscenely as she squeezed his balls, getting a glob of cum from the pressure. The effect of the short little burst was immediate, her tits growing again with a bulge starting on the base and bulging out to her nipples.

Arthur started with a moan from his nose, slowly turning it into a loud, throaty moan as he felt his cum starting to boil over from Sunset Shimmer’s urgent throat fucking. “S-Summer? I’m gonna… Gonna…” Suddenly he saw a glow and opened his eyes enough to see an orange glow around Shimmer’s horn and a smirk around his cock as he suddenly felt every inch of his balls caressed by a thousand powerful hands! Sunset was using her magic to hold up his balls as she used her actual arms and hands to pose and flex for Arthur’s delight.

And delighted he was! He roared as the first blast of cum erupted from his cock, bulging his cock to nearly twice it’s size in one thick glob of cum pushing it’s way in a pulse, Sunset groaning as he stretched her throat. The thick loads of cum, one after the other, pushed their way into Sunset’s body, her eyes growing wide as Arthur surpassed any previous amount she’d taken… even at that one football game when she was running for home coming queen back before turning good…

Her stomach bulged with cum, groaning, as it nearly burst with the sudden influx of man-goo.

Twin-Twi couldn’t resist and stepped up to the growing gurl, her tits pushing against both the back of Arthur’s balls and the front of Sunset Shimmer’s firm tits, her nipples barely dense enough to dent Shimmer’s tits, and feeling the growing tits pushing back. She reached out with both hands and caressed the massive orange tits, flexing with all her fused muscle to really squeeze the tits she’d wanted to feel for so long, in either of her previous lives.

Twin-Twi’s powerful fingers stroked across the massive, growing expanse of Sunset’s tits, her thumbs grinding against her areolas as her fingertips traced the thumping veins that worked all over the other gurl’s surface. “So much… magic!”

Still swallowing, Sunset looked up through lidded eyes at the still taller woman’s glasses and crown and smiled, bemusedly, flexing again for not just Arthur, but her best friend as well.

Twin-Twi gasped and reached out, stroking across the powerful arms, “your muscles are higher than your head!”

“Mmmm and I haven’t even gotten my full flex on.” Sunset said quickly before returning to the cock. Relaxing her arms, she focused her eyes, blushing across her muzzle before in a sudden burst, flexing as hard and big as she could. Before Arthur and Twin-Twi’s eyes, she seemed to expand in every direction, absorbing the cum he’d already pushed into her and flexing larger, thicker and bigger.

Sunset Shimmer’s massive shelf of breasts pushed out and up against Twin-Twi, who came to the realization that as Sunset swallowed more and more of the cum from those lovely, veiny, balls, that Twin-Twi was about to become second biggest again. Sunset Shimmer groaned and reached down with hands that now were finding a horse belly so big and large that she could indeed get her hands on the massive bulge in of cum inflated and vein covered tummy.

Sunset groaned as the last spurt of cum filled her belly, her whole form groaning as she tried… failed… and tried again before successfully getting that last massive load of cum down, her eyes watering as she struggled to contain it all. “Tw… Twilight? I think I might… AH!”

Twilight gasped as Sunset’s eyes rolled back into her head. Fearing her best friend was about to burst like the cum filled balloon she’d become, Twin-Twi leaned forward, crushing their tits together in an attempt to kiss Sunset, but found a face full of Arthur’s balls as Sunset suddenly expanded in every direction, especially up, pushing Arthur and his magnificent, refilling, balls back towards the uni-alicorn.

Sunset was flexing, panting, and groaning as she flexed and grew again. Her horn wasn’t just glowing, but seemed to be on fire.