“Bigger!” Pinkie proclaimed, spreading her arms in a grand gesture more suited for a podium—or perhaps, a pulpit—than her audience of one in the bakery.

“Uh, Pinkie?” Twilight said, frowning at her friend from behind the customer side of the counter. “What’re you talking about?”

“The effect of these cookies, silly. Here, have one!” The pink pony slid the tray towards Twilight, beaming expectantly.

“They are… bigger than usual cookies?”

“Oh Twilight, get with the programme, jeez! They make you bigger, of course. Or at least, parts of you,” Pinkie added, winking.

“And… That’s something I should want?” Twilight said, still eyeing the cookies with suspicion. Even if they were generously filled with chunks of white and milk chocolate.

“Oh dear, oh dear. Are we that far from a Hyperquestria timeline? No worries, Pinkie’s here to steer us home!” She waved her hand at her friend, who was growing visibly more puzzled with every other word that Pinkie said.

“Now, Twi, don’t you worry about that. Just relax, think of something nice, and have a treat. On me.” Pinkie snatched up a cookie and bit into it, spilling crumbs everywhere. “Ooh, tasty and effective. You really can do anything when you put your mind to it, huh?”

Seeing Pinkie dig in, Twilight dipped her toes in the enchanted cookie dough. “How can a cookie be effective?”

“Simple, silly. How many cup sizes do you grow?” Pinkie laughed. “I thought you were such a wiz at numbers!”

“Cup sizes? You don’t mean…”

The cookie took effect before Twilight could finish her sentence, forcing a sharp gasp from the bookish woman as her breasts abruptly grew bigger, bulging her bra to pieces and eyeing the destruction of her top, too, as they went from nice handfuls to a set closer to dwarfing her own head with boobular mass.

“That’s exactly what I mean,” Pinkie said, laughing with husky delight as her own tits followed suit. No painful bra-straps digging in for her; she knew what was coming and hefted her rapidly growing breasts with deft hands, not even bothering to repress her moan as her nipples grew fat and obscene, tenting her shirt before the size of her perky beach balls the fabric apart.

“B-by Celestia!” Twilight said, stumbling into the counter, flushed and squirming with every little touch of friction across her fat, sensitive boobs.

“Nah. By little, ol’ me. But we can fix the little.” She snatched another cookie and pushed the tray towards Twilight again. “I expected more, really. It’s a little disappointing, don’t you think?”

“Are you serious? We… we’re bustier than all of Ponyville! Combined, even! Rarity would struggle to fit a bra for your areola alone.”

“Oh, Twi. We’ve not even begun. But that’s alright, you’ll learn,” she said, smiling as she wolfed down another. “Sure you don’t want seconds? They’re good.”

Twilight’s cheeks burned so bright that any further escalation might make her collapse upon herself, like some kind of embarrassment black hole. That, or she just needed to cum really hard.

“I… I’m good,” she lied, looking away as Pinkie stripped off the remaining shreds of her top and continued with her skirt, evidently aiming for complete nudity without a single sign of bashfulness.

“Suit yourself. I’ll save you some for later.”

“I couldn’t possibly get any bigger than this…” Twilight said, trailing off. She had never even seen boobs this big, much less contemplated them hanging on her own chest—or on her friends, for that matter. How was she going to explain this or, indeed, get home without exposing herself?

Pinkie watched her internal debate with a knowing grin, uncommonly laconic as she kneaded her own far larger, and still slowly swelling, tits. As Twilight excused herself, stumbling over her words and hooves on her way to the door, Pinkie offered only a single parting comment:

“You’ll learn.”

The door to the bakery slammed shut. Pinkie was alone and undisturbed, the remaining expansion-laced cookies at her disposal. She rubbed her hands.

“Well. My boobs won’t knock this place down by themselves, will they? Might as well help myself…” She reached for a cookie, brought it up to her lips—and paused.

Pinkie laughed.

“Bet you’d like me to bite down, huh? Empty that whole tray, fill the whole bakery with my big, growing titties?” She flashed a grin, sly as a fox, as she addressed the empty room. Or rather…

“Yeah, you. You know who I’m talking to.” She winked, putting on a show of leaning over the bakery counter as her massive breasts squished between her arms. “I’m doing this for you, know! Give you a niiice, messy orgasm, reading about my growing tits. And maybe, in the process, cum a few times myself. Or a lot of times.”

Pinkie was openly rubbing her clit now, uncaring if anybody walked in on her. She knew they wouldn’t; not unless it was sexy enough.

“But if that is gonna happen, I’ll need more oomph. Beachballs? C’mon. That’s sad. My friends have started larger than that earlier in this series and didn’t even think anything of it. And I have to start in a timeline where Twilight got all flustered by growing such tiny titties? Tut tut. We’re gonna have to do so much better than that.”

She scarfed down another cookie and stepped into the center of the room (I’m gonna need the space!) with a jaunty sway of her hips.

“Now,” she said, and held her hands under her massive, shapely breasts. “Make me huge!”

***

(End of Teaser: Read the rest on Patreon)

Author's Note

4th wall break, breast/ass expansion and hyper squirting.

This one ended at 2400 words, big enough for a short story, so I've just put a ~1k word teaser here, and the rest can be found on my Patreon.