Fluttershy‘s cottage was filled with the sounds of rummaging and sweeping. Her floors and furniture were wiped pristinely clean and everything was arranged exactly where it should be. Different to Discord or Rarity, who appreciated and didn‘t mind a bit of a mess, she was afraid if Twilight saw a hint of unorganized decor, she would start fixing it herself, and the pegasus could not allow her guest for afternoon tea to start cleaning after her.

Really, she was glad Twilight came forward and asked her to come over. The bookworm had once again been holed up in her study on an experiment. She didn‘t say what it was, but magic was bound to play a role in it. The fact that Twilight approached her was probably a sign that it had gone well. Probably. Though a certain feeling did nag in the back of her mind. Why her? Did her experiment have something to do with the shy pegasus? Fluttershy knew Twilight well enough, and trusted her enough to not think the worst from it. It was simply going to be a relaxing afternoon tea, where Twilight could rave about her studies.

The knock on her door was enough to alert Fluttershy that her friend had arrived. A smile spread on her face before quick steps tapped over to open her door. „Why hello Twilight, it‘s so nice to see… you?!“ The smile Fluttershy sported was quickly replaced by a look of… bewilderment, was probably the best way to put it. She expected to open the door to Twilight in her usual, comfortable, but professional attire. A pleated skirt, plain blouse, a pair of thigh high socks, etc. to be honest, most of it was still present, but… different. To start, the skirt was way shorter than before, accentuating her friend‘s broadened hips that now flared out further than her shoulders. The thigh high socks stayed, but they now clung to legs that stretched far longer, giving the usually smaller unicorn a stature that rivaled even Applejack in height. As her eyes drifted upwards, they followed Twilight‘s newfound hourglass figure, giving her more curves than the road to Canterlot, and exposing a toned midriff. Her tummy was usually covered by the blouse that now stretched over a pair of breasts that seemed even bigger than Fluttershy‘s own. It wasn‘t like the pegasus took any pride in her own bust, but seeing Twilight, one of the flatter girls in their friend group, suddenly sport a cup size loser to Celestia‘s own was… different… to say the least.

„Woohoo, Fluttershy! You in there?“ A few seconds must have passed, Fluttershy realized as Twilight pulled her out of her stupor with a stupidly cute knock to the pegasus‘s forehead. Her gaze shot to the unicorn‘s face for the first time since she arrived, she noticed. Twilight never wore makeup, but today, her face was decorated in mascara, eye-shadow and lipgloss. „Can I come in?“, Twilight giggled further, before the yellow pony allowed her in. The Twilight in Fluttershy‘s memory was wildly different from this… floozy? Fluttershy wasn‘t sure if that was too mean a word to describe her friend‘s transformation. But to go from the studious and serious librarian or school girl to this?

„Golly, Twilight. I’m just a little shocked. Did you… uhm… your experiment…“, Fluttershy could not find the words to describe her utter confusion, much less over the racing heart in her chest, her face flushed red from how provocative her friend was dressed. She placed her hand on her chest, feeling her heartbeat and telling it to slow down, but it just wouldn‘t stop as she watched her friend saunter to her tea corner.

„Yeah, it was a full success! Pretty obvious isn‘t it?“, Twilight beamed as she took her seat. Levitating her cup and sugars to her hands with magic, Fluttershy could see she was just bursting with positive energy. That fact alone was enough to ease Fluttershy‘s mind a bit. As long as Twilight was happy, this couldn‘t have been so bad, right? „You remember that talk we had the other day? About Rarity and Cadence‘s dress?“

Fluttershy did remember, and honestly, she had suspected that it was about exactly that. Rarity had lamented that she had just finished a dress for a ceremony in the crystal empire, when it turned out she needed to increase the bust size. Apparently, Cadence gave her the wrong measurements. This quickly turned into a conversation between the girls about, to quote Rainbow Dash, „how utterly stacked the Princesses were.“ While nobody present was going to deny that fact, Rainbow‘s tone did strike a nerve with the one princess present that didn‘t share a bust size above DD with the others. Twilight was just barely hitting a C Cup, at least a couple of days earlier. Now, Fluttershy could swear she could drown her face inside her friend‘s cleavage. In fact, her eyes were already getting sucked back to that cleft of titmeat, her desire to just have that rack suffocate her growing as well.

Shaking those thoughts out of her mind, she focused on their talk again. „Well, I think you looked lovely even before your… experiment. But as long as you‘re happy with your body, I will support you!“, the pegasus declared, sipping from her cup as her eyes kept getting drawn to Twi‘s body, almost hypnotically.

„I‘m so glad you think that way. I had a feeling you‘d be the most understanding. Applejack would probably dismiss it as impractical, Rarity would drag me to get my measurements and make dresses, and Pinkie and Rainbow would probably just want to play with my new boobies!“, Twilight explained, lifting up her new bust for emphasis. The sudden motion made two buttons pop, her chest quite literally spilling out of its confines of fabric. Seeing Twilight‘s dark, purple nipples peek out from behind the fabric almost made Fluttershy choke on her tea, if she hadn‘t spit it back into the cup and coughed up the rest.

„Oh, uh, uhm… D-don’t worry, I‘ll have that fixed right away“, Fluttershy needed a moment to breathe. Her heart was racing too fast, she was breathing too hard. Her chest felt too tight inside her sweater… her pants felt a little tighter too, but she couldn‘t focus on it. Twilight‘s new body just… did things for her. This Goddess among ponies, she wanted so much to just be smothered in that cleavage. She felt her panties wet and her pussy drip. She noticed how hard her nipples were under her strained sweater, and the thought of Twilight noticing it under the fabric was sending the flustered mess of it all to even greater heights. Was Twilight doing this on purpose?

Once she steeled herself and went back, sewing equipment in hand, Fluttershy found Twilight relaxing in her armchair with a sultry look on her face that made her friend‘s heart skip even more beats. „Come on, sit!“, Twilight issued an order with… unexpected authority, though she did not point to the chair opposite of hers, but down to her scandalously short skirt. The command sent shivers down Flutters‘ spine, but she felt obliged nonetheless. How could she deny Twilight anyhow?

As she sat down on Twilight‘s lap, their breasts got squished together. There was no way in Fluttershy‘s mind that Twilight didn’t feel her diamond hard nipples even through three layers of fabric. The princess didn’t let it on, simply letting Fluttershy attempt to fix her button. Try as she might, her hands could not keep the needle steady. „You know, you don’t need to fix it!“, Twilight offered with a wink that made Fluttershy drop the thread entirely. The pegasus needed to remind herself to breathe to not pass out.

„I, uh… What do you-?“

„I can see you‘re enjoying my new body. I don‘t mind, you can enjoy it a whole bunch more!“ Just as Fluttershy was about to swallow, HARD, the lump in her throat grew as she felt something else grow as well. Fluttershy‘s jaw went slack as she gazed down at the massive piece of meat swinging and bobbing between Princess Bimbo Twilight‘s legs. She could swear it was as big as her entire forearm… maybe even her lower leg. She couldn‘t tell anymore as her body kept changing.

Without Fluttershy even knowing it, just being in the mere presence of Twilight‘s dick seemed to transfer the effects of Twilight’s experiment over to the pegasus. As she stared at that thick cock, her plump legs grew longer, more squishy, until she swallowed Twilight‘s lap entirely. Flutters‘ tits, already the biggest in their friend group, ballooned right into the unicorn‘s face, much to her enjoyment as her research proved to be successful. The threads in Flutters‘ jeans pulled taut while her sweater shrunk down in size. Without tearing, the magic simply seeped into her garments, molding the wool into a crop top with a sizable boob window for Twilight‘s face to rest in, until the unmistakable tear of jeans ripped through the cottage.

Fluttershy simply watched as her fat ass spilled out of the tear in her clothes, watched as the massive cock bobbed to full size and let out a moan as the slab of fuckmeat slapped against her bouncy butt cheeks.

„It seems the more the subject had to begin with, the more they will grow afterwards“, Twilight hypothesized from between Flutters‘ breasts, just enjoying the sensation of her friend‘s body against hers and her dick. „Or maybe some other factor plays into it. I have to test it further, but for now, how about we just have some fun? Look at me!“, Twilight told Fluttershy in that sultry commandeering voice that made the shy girl swoon, right as a meaty spank to her ass rippled through her thicc meat.

Just as Twilight thought, Fluttershy‘s face morphed a bit as well. Newly plumped up lips were painted in pink lipstick, while her eyes shimmered in golden eye shadow. And the surprised, vacant look on Flutters‘ face was enough to make Twilight lick her lips. „You want this, don‘t you?“

Even if Fluttershy‘s brain was still able to function enough to speak up, all semblance of resistance went out of the window as Twilight shoved her thumb in between those thickened lips and she just started sucking on it. It felt so good to just suck on it. Fluttershy was so happy to just suck on Twilight‘s thumb, her body started moving on its own, shaking her hips on Twi‘s lap to make her ass cheeks bounce around that thick cock. She couldn‘t help but moan around the purple finger, hugging her friend deeper into her cleavage.

„Of course you do. Why wouldn‘t you want to please this cock. So thick, it would still fit perfectly in your ass, don‘t you think?“ Twilight‘s words rang in Fluttershy‘s mind, almost hypnotically, but she couldn‘t say whether the words had any sway in her actions, or if the yellow mare plunged the purple horsecock into her asshole on her own. The howl that erupted from the two shook up the birds outside the cottage. Flutters‘ eyes rolled up as she threw her head back. Though she stopped for a moment to get used to the sensation, Twilight wasted not a second to start thrusting into her friend‘s ass. It was even better than she could have expected.

The pinkette‘s insides were insanely hot and tight. Never in her life would she have expected such a frivolous outcome, but she was embracing the hot insanity wholeheartedly. Twilight lost herself in the sensation and began to take command. Standing up from her seat, she threw Fluttershy onto her back, supported by the cleared out coffee table and her head laying on her former seat. Fluttershy was too busy moaning to speak up about the rough treatment. Not that she would have, tits flopping out of her new sweater.

„Fuuuuck, slamming into your ass is so good. I should have done this years ago. I‘m like, so glad I gave you my dick virginity!“, Twilight let out in debaucherous moans, her lips stretched into a lewd smile as she watched her friend get buried under the weight of her growing tits. The table creaked and cracked from the increased weight and intensity of the thrusts. Both mares lost in hedonistic pleasure, Twilight sank into the abyss of tit flesh to try and give her friend a kiss. The moment their lips locked, tongues intertwining in a sloppy dance, Twilight‘s cock erupted, filling Fluttershy‘s ass with her white, gooey spunk with a bit of pink shimmer to it. The pegasus roared out in pleasure as a final growth burst made her tits the size of beach balls, the table collapsing underneath them and their sheer weight.

Both bimbos laid there, panting and kissing. Twilight peppered Fluttershy in kisses while the pegasus simply tried to keep up with Twi‘s lips, her eyes half-open from exhaustion, just relishing the feeling of hot, steamy cum sloshing in her guts.

„Hey, you wanna do more rounds on your bed?“, Twilight offered a more comfortable location as she pulled Fluttershy up from the ground, her entire body jiggling with each movement. Fluttershy‘s mind was too absent to respond, but followed anyway, eagerly.

„Oh, I have got to get the others in on this too!“, the purple bimbo thought to herself before throwing herself on the pegasus once more.

Author's Note

Hope yall like futas and bimbos!