No pony could tell the exact moment the timer ran out. The stage was a swamp of creamy semen overflow, barely an inch of the original wooden boards left uncovered. Gobs and globs of white molasses quivered at the edges, threatening to spill over the audience at any moment. The air was humid and warm and stank of sex, so thick and musky a pony could worry they’d get pregnant just breathing it - even a stallion. Some of it had even managed to leak into the tall hourglass standing at stage center, all its sand mixed into a soupy, sludgelike pool.

Just a taste, and a smell, and a very sticky touch, of what a pent-up Princess could manage.

“Oops!” Twilight giggled, leaning smugly back into Pinkie’s filled-full belly. “Sorry, Trixie, I thought I was already finished.” She laughed again, a hint of royal guile in her smile. “When you make as much as I do, it can be so difficult to tell!”

“A likely story, Sparkle.” Trixie dropped her magic shield, a good quart of what had been stuck to it splattering over the floor... and onto her leggings. An uncomfortably warm feeling ran up her calves, the piping-hot potency of Twilight Sparkle smeared all over her dazzling new stage outfit. She grimaced and glowered. “Trixie is wise to your games, do not think she isn’t! And it shall not go as you have planned, either.”

“Oh?” Twilight raised an eyebrow in quiet amusement. “Mm, I guess I really can’t fool you, Trixie. You saw right through me. I didn’t really think I was finished.” A glance between her legs told the truth of that. Her royal balls were even bigger now, if anything, a sexual fire fuelled to even greater heights by Pinkie’s expert pleasuring. There was a slow, pendulous weight to their motion as they rocked and sloshed, slapping gently against her thighs with every mischievous sway of her hips. She winked. “How could I be? Pinkie’s only my warm-up help. I still need to claim my real prize!”

“Your prize!” Trixie scoffed, the thrill of victory rushing through her. “Look around you, Sparkle! All you have done here is waste your pathetic little load, granting the Great and Powerful Trixie her victory!” She patted the bloated butter-yellow tummy of her assistant, a gentle wave of motion radiating outward just beneath her fur. “Trixie has filled your enormously uddered cow beyond all compare, as even you must be able to see.”

“Mmhm,” Twilight nodded. “I do see.”

And so did every pony watching. Both assistants had been made truly huge, rendered round and immobile by their partners’ productivity. Trixie’s filling had certainly done a number on the well-fed Fluttershy, but prodigious Pinkie was another order of magnitude bigger, a cum-bloated blimp to Fluttershy’s helium balloon. While Fluttershy’s jiggling stomach might have made a nice enough waterbed, Pinkie’s was the start of a rippling bounce castle. A field of pink big enough to walk on, if one could dare to put that much pressure on her. Fluttershy’s head could be made out from a far enough distance, a mane of pastel pink against the soft yellow background of a voluminous stomach. From a full pony’s height above her, a still-bigger Pinkie waved down with a pudgy black-gloved arm, setting ripples through the miniature hillock of her truly titanic tummy. “Hi, Fluttershy! How’s the weather down there?”

“Oh, um - erp!” Fluttershy paused, a bubble of precum rising up around her lips. “Hello, Pinkie… It’s fine…”

Trixie’s mouth fell open in shock. “No!” she shrieked. “No, no, no! Not again! It can’t be possible!”

“What?” Twilight asked coyly. She looked casually over the imposing pink zeppelin her partner had blown up into, a proud little smirk on her face. “Oh, this? Well, didn’t we tell you, Trixie? Anything is possible with the power of friendship. I think this one is a win for Team Twinkie, don’t you?”

A dozen straining and puffing ponies were tasked with rolling both of the inflated assistants off, to a nice, secluded place where they could process their loads in peace. The both of them would look forward to growing a good deal wider over the next week. Such high-calorie, protein-rich meals didn’t come without consequences! Even now, the stage itself could barely handle both of them at once. The floorboards creaked wearily as they were freed of the stress of those tanker-like bellies, ready for a well-deserved rest of their own.

“As I was saying earlier…” Twilight started. She strutting up toward Trixie until they met each other flare-to-sticky-flare. The difference in size, so minor before, now left a threatening, almost hungry shadow over Trixie's wand. “My real prize. You do remember what you said the stakes were, don’t you, Trixie?”

Trixie fell silent, her mouth uncharacteristically shut, some horrible great clutch in her throat. This was not how it was supposed to go. It was supposed to be her gloating right now, bending Sparkle over like a cheap whore… In all her wildest fantasies of how this contest would end, she had forgotten the very real chance that it wouldn’t be in her victory. She twiddled her fingers together, nervously eying Twilight’s enormous purple rod as it oozed growing streams of clear precum over her own. “Evrrthn,” she finally muttered.

“Hm? What was that?” Twilight dragged a finger over her shaft, a thick strand of liquid sex trailing along as she pulled it back. “Come on, Trixie, don’t you remember you’re on stage? The crowd has to be able to hear us~”

“Oh, alright!” Trixie growled. “Everything! We bet everything on this contest.”

“Mm, yes, that’s right. Everything.” Twilight closed her eyes, lips parted ever so slightly as her horn began to glow. “Don’t worry, Trixie. Just think of this as your first lesson: good friends will give as much as they take.”

And she was prepared to take quite a bit. Trixie’s eyes went wide as she felt her own cock - her pride and joy - suck inward, its length retreating, receding. A pleasantly cool haze settled over her thoughts as it happened; her front-heavy build suddenly felt so much easier to balance, balls the size and heft of watermelons shrinking into cantaloupes, contracting into apples. For the first time in years, there were stallions who could call themselves bigger than the Great and Powerful Trixie! What a scandal, what an outrage, what a strangely delightful feeling…

“Ooh, I’ve been waiting to test this spell for such a long time, Trixie. I hope you don’t mind going first.” Where Trixie’s dick retreated, Twilight’s advanced. Inch upon inch of fresh, wet flesh poured out from her crotch, thick and musky with her own royal virility. The two cocks maintained their gooey embrace, an ever less equal match as a surge of purple shoved Trixie’s blue backwards. Her already vast balls gurgled audibly as they grew still riper and fuller off Trixie’s stolen productivity, Twilight’s formidable pony-filling prowess enhanced still further by her rival’s magic. She could only smile as her overripe seedpods squished against her thighs, churning with the delicious ache of too much seed to hold. If only, if only she had some place to put it all…

A place usually full of nothing more than hot air, for example.

Trixie sighed as her once-massive cock finally melted back into her fur, giving her puffy pink lips their first taste of cool air since magical puberty… Only to be plugged once more by the steamy heat and sudden pressure of Twilight’s enormous flare. She jerked and shivered as a shock of pleasure ran up her spine, completely unused to being poked in such a place. She gasped, suddenly lucid. It should have been her doing the poking! “Do not think Trixie is enjoying this, Sparkle. I will have my revenge for this!”

“Whateeever you say, Trixie,” Twilight said. It was all the same to her, cute little moans or feeble denials. She seesawed her hips back and forth, dipping her tip between Trixie’s slender legs. Already bowed out for a prick's presence - how convenient! With such an enormous cock came a truly untameable need, one that tested even her famous willpower. A blink of magic, and she was behind Trixie, a good distance away to accommodate the full length of her third leg. “I think that’s enough taking for me. Why don’t I give you back some?”

“Don’t you dare, Sparkle!” she hissed, even as her body leaned instinctively forward, her rear back and tail flagged in graceful, classic presentation. The air was awash with studly masculine pheromones, the interest of truly virile stallion made abundantly clear. Her body practically demanded her submission to Princess Twilight, whether or not her head agreed yet. “It is bad enough that you have humiliated Trixie so already, but to fill her like some common cum dumpster! Why, Trixie will-”

The deafening schlorp of Twilight’s abrupt entry cut her off completely, the air shoved from her lungs by a titanic endowment. Trixie was stretchy - magically so, from all her spellwork, but this was beyond all else. Beyond even her own hasty dreams of sexual achievement, half-fevered sketches of grand tricks cast completely aside! Twilight’s passion was enormous, huge and unrelenting beyond all belief. Everything seemed to shut down, every thought and inhibition replaced by the overriding reality of Twilight’s cock. It was big, massive - whatever word she wanted to use, it was all that and more. She could feel her every internal process shifting, struggling desperately to make room for what was already there even as Twilight pushed in more. Her slim toned stomach bulged outward, the imprint of Twilight’s influence clear to all as quarts of copious precum saturated her. The shoddy material of her blouse ripped immediately, leaving her burgeoning belly exposed for all to see.

“You’re doing a great job, so far, Trixie.” Twilight waved to the awestruck crowd, her magic keeping Trixie steady as she drove deeper and deeper instead. Hardly an hour ago she might have already bottomed out, but now with Trixie’s generous assistance... Well! Her commanding medial ring was only just slipping inside that tight and delightful pussy, and she had more than enough left to keep her new cocktoy in suspense. She thrusted again, a little out and a little more in. A low, throaty moan escaped her lips as Trixie gasped and squealed. Oh, no wonder Trixie loved the stage so much. Fucking such an adorable, stretchy pony was nice enough, but having an audience to watch her dominate her former rival brought every sensation to a new high. “Look! They love you!”

Trixie could hardly notice the cheers, all her attention focused squarely on something more immediate. Something much, much bigger. The dull throb of Twilight’s pulsating cock rung loud in her ears, the first load of sticky cum like a rushing river. There was no teasing or build-up here. This was animal. Twilight needed to unload, and she needed it now. Gallons and gallons bloated her in seconds, her tummy dropping down to her knees in an instant. All the weight she’d lost in front with her own endowment was returned with interest, repurposed as an impossible load of Twicum. And that was only the first. There seemed no clear end to Twilight’s orgasm, only spurt after spurt of heavy cream for her to take in. Any thought of struggle, of resistance, of proving she wasn’t merely a condom for Twilight Sparkle had been stopped dead in its tracks, encased within a layer of gooey alicorn batter.

A long, gooey struggle for Trixie was a heavenly ride for Twilight, fingers dug into Trixie’s swollen belly as it grew big enough to bulge out behind her. Pinkie would always be the better cum balloon, of course, but there was a special satisfaction in doing this to the Great and Powerful Trixie… or was that now the Meek and Powerless Trixie?

The physical pleasure was nice enough - anything could get her off, big and horny as she was now - but the real treat was knowing just how utterly in charge she was. If she wasn’t already stuck mid-orgasm she might have cum just from watching Trixie’s tummy droop to the floor, until it swept her right off her own hooves. The both of them rose slowly into the air as an endless stream of cum poured forth from her balls into her former rival, a grand show of dominance on all levels. Physically, mentally, sexually. In every category, Twilight Sparkle topped Trixie.

Trixie could hardly argue with the facts. “Uuungh,” she moaned in submissive satisfaction, her arms roaming over her swelling stomach as she ascended into the sky. Far from shame that the whole town of Ponyville could see her bowing down, and bulging out, she felt pride. Only Trixie, talented as she was, could take so much of her Princess’s cum. More and more every second, filling every nook and cranny with deliciously satisfying warmth - and making space where no more could be found. No, it wasn’t pity she saw in the eyes of her captivated audience. It was envy. They wanted Twilight Sparkle’s notice, her cock, her vast oceans of cum. All things she alone had now!

The stage creaked and groaned beneath her liquid weight, the wooden construction unequal to Twilight’s tremendous loads. Trixie grinned as she felt the first boards snap beneath her. The more Sparkle gave her, the better she felt. She was gigantic, invincible, all-powerful. A goddess among ponies… so long as she took everything her Princess had to give her, like a good cum dumpster should. The flooring finally gave way beneath her, a thunderous crack as wood snapped, followed only by a muffled whumpf as Trixie followed suit. What should have been a cataclysmic crash to earth was instead the gentle fall of an overstuffed pillow, multiplied by a thousand to capture Trixie’s squishy enormity.

Only the rims of the stage remained now, and unstable cradle that couldn’t hope to contain her if she grew any bigger. If only she could have. She could feel already that this was the end - or an interlude, at least. The once endless rivers of Twilight’s cum had finally relented to trickling streams, then eventually to a stop. Finally, fifteen long minutes after her orgasm had begun, Twilight was finished. It took her nearly a minute more to pull all the way out, full feet of cock sliding out from the comfortable sleeve of Trixie’s body. Even pumped as full as she was, beyond any other pony in the whole history of Ponyville, Trixie couldn’t help feel a little empty after it had left. She wanted more, needed more. “Wait, Sparkle!” she cried. “Is this all you will be giving Trixie? It can’t be!”

But Twilight seemed deaf to her words. The crowd cheered as she emerged at the top of the tremendous blue bulwark, holding both lavender arms high to acknowledge their admiration. She was smiling wide enough to split her face, a light sheen of sweat brushed over her fur. They’d been promised a show, and by Celestia’s almighty name they had been given one.

“Thank you, thank you, everypony!” she said, taking a bow from her perch atop the blimp. Her cock, already low to the ground, fell low enough to dab another sticky marking on Trixie’s fur. “I certainly hope you enjoyed our performance here today.”

“Pah!” Trixie shouted, struggling to rock and roll herself over to no avail. “No, Sparkle, that can’t be all! It ended too early!”

“...Please exit in an orderly fashion. No trampling over each other like last time…”

“Hmph! Fine, then.” She would have crossed her arms, if they could have reached each other across her stomach. “See if Trixie cares. She does not need more if that is all you have.”

“...Souvenirs and merchandise will be sold at the castle, if you would like to buy any. Ask for Spike, and he’ll…”

“Oh, well.” Trixie sighed, nearly ready to give up hope. It seemed that even among the princesses of Equestria, this was the limit of what she could get. “How… disappointing.”

Then, suddenly, her ears pricked up as Twilight’s final words reached her: “If you would like to see another show just like this one, be back in just half an hour. Tell your friends to come, too! And don’t worry about them missing anything if they can’t make the next show, either…” She could nearly hear Twilight’s grin in the pause that followed. The suspense building just as surely as that limitless sex drive was readying Trixie’s next filling. “...We’ll be here all day.”