"I can't believe you of all people would do that."
"I didn't do anything they didn't start."
"Don't talk back to me," Ms. Grace snapped. She was pacing, wearing out her heels on the gymnasium floor, and squeezing her hands together. Though dressed for work in a sensible shirt and skirt combination, Mia only noticed the swell of her curves, shapes obvious against the clothes as if trying to rip themselves free. She was wearing a bra, though with the errant drip of fluid from her legs, it was doubtful she had panties on. Why did she have to act so outraged?
It'd be so much simpler if she acted as her students did and just gave in. More words dribbled from her lips, meant to demean Mia for her unintentional actions, much as she was enjoying their results, yet she paid little attention to the human. It was just a matter of time before Ms. Grace lost control of herself. Instead, Mia looked around.
The gym had become a stranger to her since the surgery. Hooves weren't really designed for indoor exercise, instead she just ran around the fields at her old home and occasionally lifted weights to keep her upper body fit. Not that she needed to anymore. Every second that she grew, her muscles compensated, sometimes too much. Already her flat stomach was dimpled with abs.
Of course, the same spread to her equine body as well. Anyone could tell she was a prime stallion at a glance, even ignoring the obvious virility of her sex. Striations ran across her form, always moving as she grew and her weight shifted slightly. The wooden floor beneath her groaned under her form, only masked by Ms. Grace's aggravation and Mia's shirt nearing the end of its short life. It constantly groaned under the strain of her growth.
Entire inches of breast size seemed to appear between blinks. That couldn't be true though, otherwise she'd be so much bigger already. Hitting her head on the rafters, accidentally destroying them just by growing even more, or she'd fill out the gym. Her cocks weren't against the idea as they kept spilling pre-cum.
"Are you even listening?" Ms. Grace asked.
"Hmm?" Mia tilted her head back to look at the human, no longer even half her size. What power did this small creature have over her? She frowned at her thoughts and ran a hand through her pink locks. Of all the abnormalities of her body, the colour was the only thing she chose for herself. For almost a week now, it did whatever it wanted, growing and seducing and fucking. Or were the last two her decision? It wasn't like she couldn't control herself anymore. She hadn't jammed Ms. Grace on a cock yet and she wanted to.
"Mia!"
"Huh?" The centaur looked down again, hands slipping from her breasts she hadn't realised she was groping, and saw her cocks nudging the lecturer, closing on all sides. Mia stepped away.
"Clearly you're in need of discipline. Drastic measures are necessary," Ms. Grace muttered, chewing on her lip, and rummaged through her purse. Mia hadn't even noticed it until then, "And these will help." She pulled out a set of metal cuffs, with a chain hooked into a loop that produced a series of clamps.
Mia restrained a laugh, "Those aren't big enough for my wrists."
"I-I know," Ms. Grace said, face turning tomato red, "That's why I've got these." This time, she revealed a bunch of zip ties, which she wove together until they could handle the centaur's size. Few humans had strength enough to rip them apart. Mia flexed, studying her arms as muscles bloomed across them; maybe she could?
"Bend down."
Mia obliged. If nothing else at that moment, she was cordial, happy enough to humour this person until the inevitable happened. God, what was she becoming that she was so fixated upon it? This woman, a teacher at the college since before Mia enrolled, was trying to lecture her and she could focus on nothing but the prospect of fucking her. It wasn't her fault, not entirely, given how close she'd come to getting off earlier. She should've fucked her new housemates that morning.
"There, feeling the weight of your actions now?" Ms. Grace asked, having tightened the restraints so the durable plastic bit deep into Mia's wrists.
"Yes," Mia said, though her cocks throbbed, drooping further as they grew. Was her teacher into BDSM, did she dominate people in private? She licked her lips, a unique tingle fluttering through her loins. Who was Ms. Grace to even think she could dominate her? "What next?"
"Next? I... what happens here doesn't leave this place, understood?" Mia nodded, "Good. Words aren't enough for someone like you. Nothing but a beast in season, looking for the nearest female to mate." From Ms. Grace's purse, a tight knot came out, then unfurled into a cat o' nine tails. She whipped it through the air, wind hissing around the many lashes.
"Shirt off."
Mia stripped her sole piece of clothing. She expected it to snap back into its former shape, given the strength of the elastic and, while it did shrink, the shirt had seemingly tripled in size. How long would it last against her and, for that matter, how long would Ms. Grace? All notion of punishment left the teacher's mind as she gawked, eyes reflecting the majesty of Mia's chest, so huge it could support a small class. If Mia held them together and she climbed into the cleavage, she doubted she'd ever see light again.
"What next, Ms. Grace?" Mia asked, an unintentional huskiness in her voice.
"Um, next is... right, yeah, next is punishment. For being so lewd in class."