Derpibooru ID number: 972580
Artist: Phurie

Streetch, snip, snap. Twilight watched with quiet interest as the final straps of Pinkie’s outfit failed to contain her. The pudgy pink pony was expanding in earnest now, her belly so swollen and bloated with cum it could be seen from behind. It was just like watching a water balloon fill from the tap; every tense, every twitch of her heavy, pendulous balls reflected in the gallons of thick, creamy cum pumping into her friend’s burgeoning form.

And that was barely half of the full proceeds. Pinkie had always had a positively prodigious metabolism, digesting cakes and burning through calories so fast she could nearly plump up in real time. A good thing, too, Twilight thought smiling, eying Pinkie’s ever-thickening rear. If she couldn’t, she might have popped by now.

But a good scientist left no limit untested, no boundary unbroken. She simply had to see just how much Pinkie could take, considering just how much she had left to give... “Hope you enjoyed your appetizer, Pinkie~” She sighed and bucked her hips, curling her fingers in Pinkie’s mane as the next wave of orgasm broke over her. Spurt after spurt of piping hot seed, made with love, flowed down Pinkie’s throat in an endless stream.

Pinkie’s grip tightened, too, arms wrapped around Twilight’s thighs in a loving hug. She could barely speak now, lips sealed tight by the swell of Twilight’s medial ring, but her eagerness for more showed in every drop she swallowed. A slow, rubbery, stretching sound filled the air as her cum-filled tummy reached earth, more and more pinkie pudge swelling over the floor by the second.

They weren’t done yet. Not by a long shot.