I used NovelAI's unlimited gen membership for $25 a month. Note that "unlimited" is kind of a lie, it's only unlimited if you're under a certain resolution and only if you're not using any of the advanced features. Upscaling and other features cost the on-site currency, which the membership gets you 10000 a month. That should be more than enough for a month, but you can burn through it quickly since NAI gens so quickly.

The warm afternoon light poured through the tall bakery windows, turning the whole room into a golden haze of sugar, vanilla, and pure celebration. The air was thick with the sweet, buttery scent of fresh-baked muffins mixed with the heavy, rich aroma of pink-frosted birthday cake. Confetti still drifted lazily through the warm breeze, pink and blue ribbons fluttering against the ceiling like living butterflies. Laughter and soft, happy music played in the background — the kind of cheerful, bouncy tune that made everypony’s heart feel three sizes bigger.

And then there was Pinkie Pie.

She sat on the edge of the big wooden cake table like she owned the world (and she basically did), her enormous, heart-shaped ass raised high and presented right at you like the most ridiculous, delicious, and over-the-top birthday cake in Equestria. The thick, wobbly pink flesh of her mammoth ass was glistening with thick, glossy white frosting that slowly dripped in heavy, creamy trails down the deep curves of her cheeks. Candles — bright red, blue, and yellow — were stuck into the soft, warm-looking flesh of her ass like it was the world’s largest, most playful birthday cake. Sprinkles and little balloon-shaped candies popped against her skin with every tiny movement.

Her bright pink mane was a wild, fluffy explosion behind her, and those huge blue eyes sparkled with pure, unfiltered joy as she looked back over her shoulder at you with the biggest, goofiest, most seductive smile you had ever seen.

“Eeee! There’s my favorite pony!” Pinkie squealed, voice bright and bubbly like warm party bubbles. She reached back with one hoof, gave her own massive ass cheek a loud, playful *SMACK!* that made the whole table shake and sent a wave of frosting and sprinkles flying. The sound was wet, meaty, and deliciously loud. “Look at this big, wobbly birthday cake! It’s so soft and squishy and… mmm… it’s all warm and sweet and covered in my special frosting! Just for you~!”

She reached back again, grabbed one cheek, and pulled it open just a little, giving you a full, wobbly, jiggling view of the creamy pink flesh. The scent of her body hit you — sweet pink sugar, warm skin, and that unmistakable, spicy musk of a very, very turned-on Pinkie Pie. Her pussy was visibly dripping, a thin string of clear arousal stretching from her swollen clit down to the table.

Pinkie giggled, the sound high and giddy. “Ooooh! Did you like that smack? It’s so big and bouncy and wobbly, just like me! I made this giant cake all by myself just for you, you know~! Every single candle is waiting for you to blow them out… but I bet you’d rather blow out something else first, huh?”

She gave her ass another loud *SMACK!*, harder this time, the pink flesh rippling and jiggling in a hypnotic wave. Frosting splattered across the table. One of the candles flickered and popped like a tiny firework. Pinkie’s eyes went wide and sparkling with excitement.

“Wooow! Look how much frosting is dripping down my big, fat ass! It’s so warm and gooey and it smells so sweet… like birthday cake and me all mixed together! I’m so happy right now, I could burst with joy! But mostly because you’re staring at my cake and it makes me so, so happy~!”

She turned her head just enough to wink, tongue poking out playfully. “Mmm… I can feel you looking. I can feel your eyes on my giant, bouncy, frosting-covered ass. It’s so huge and soft and warm… I bet it’s even bigger and softer than all the cupcakes in the whole bakery! You want to squeeze it? You want to smack it? You want to bury your face right here and eat it like the best birthday cake ever?”

Pinkie reached back with both hooves, spread her cheeks wide open with a dramatic *SQUEAK!* of the flesh, and wiggled her hips so the whole mammoth ass jiggled and bounced. The candles on her ass flared brighter, as if they were excited too.

“Eeee! Look how wobbly it is! It’s like… like the softest, squishiest, warmest cake you could ever imagine! And it’s all dripping with my special birthday frosting… and it’s all for you! I made it just for this moment, just for this look on your face… and it’s so big and bouncy and I love how it feels when I smack it… it’s so much fun~!”

Her voice dropped into a silky, teasing purr as she gave her ass one last playful *SMACK!*, the sound echoing through the party-filled room.

“Mmm… you like my birthday cake, don’t you? You like my huge, wobbly, frosting-covered ass? Then come closer… I want to hear you say how much you love it. I want to hear you beg me to let you eat it. I want to hear you tell me how much you love Pinkie Pie’s giant, bouncy birthday cake~!”

She smiled at you, eyes sparkling, tongue out, one hoof still spread wide on her jiggling ass, the other still smacking her cheek every few seconds just to make the frosting and candles dance.

“I’m so excited for my birthday… and I’m even more excited because you’re here, looking at my cake like you want to eat it… and I love it when you look at me like that~!”

The confetti kept falling. The candles kept flickering. Pinkie’s mammoth ass kept bouncing and jiggling as she teased you with every playful smack and every bubbly, sexy word.

And somewhere in the warm, sugary air of Sugarcube Corner, the biggest, bounciest, most delicious birthday cake in Equestria was waiting… all for you.