Rosie let out a sigh of relief as Kat and Andrea began sucking on her giant, full tits. Finally, the pressure was subsiding.
Andrea had originally planned to take the milk and spit it out, but as soon as she’d gotten even the slightest taste of it began to take big, greedy gulps. Kat did the same, swallowing as much of the sweet, creamy treat as she could.
Immediately, the girls started changing. Their stomachs flattened, abs forming. Their body hair receded and disappeared. Any flaws in their skin corrected themselves. Both Andrea and Kat’s breasts grew; their hips and rears followed soon after, giving them huge breasts and massive asses just like Rosie. Their scent changed right after, their armpits now letting out equine musk filled with pheromones.
Of course, the two girls were completely oblivious. Kat’s gothic makeup became far sluttier, her lips puffing up and the pigments becoming permanent as her skin paled even more; her dyed black hair naturally and permanently turned that color as her eyes moved to the top of her head. They elongated, turning equine as they gained matching midnight black fur. A tail sprouted above her now much larger ass, its own silky fur matching her new ears. Her hair stylized itself into long pigtails.
Andrea went similar changes, but her hair remained a light brown. Her new ears and tail matched her hair, and the bun in her hair burst as her hair thickened up, her silky brunette hair flowing down her back.
Both girls’ nipples became permanently erect and pushed out, becoming thumb sized to match their new huge tits. Their final changes occurred next as their genitals changed; their assholes became equine, as did their vaginas, as horsecocks and testicles grew above their new vaginas. As their transformations finished, Kat and Andrea finally relinquished their vacuum seal on Rosie’s nipples and immediately orgasmed, moaning as loud as they could, filling the holding cell with semen, milk, and squirt as Rosie came along with them.
Reality altered as the normal holding cell they were in changed; now, it was made specifically for horse herms. A drain in the middle collected all of the bodily fluids that the three released, and the trio collapsed on to a soft, padded surface, much more comfortable than the cell had been before.
With none of the girls any the wiser, they’d gone from normal college students to equine sluts.