Casimir had given Grey the following day off. In his experience, most new arrivals needed a day's rest before their minds were clear enough to even pick up on training cues.
Instead he went to work getting a cap fashioned for the unicorn's horn. With the aid of a jeweler, he came up with a rounded gold cup with little barbs on the inside - it would slide on easily, and it couldn't be removed without tools. No more risk of getting stabbed.
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The next morning, Grey awoke to the rattling of keys. It jumped to its hooves, and was brutally reminded of the tight collar still around its neck, and the too-short chains holding it in place.
"Good morning Grey. I hope you slept well," the prince said nonchalantly, as if speaking to a colleague rather than a prisoner.
"You know damn well I didn't."
He ignored the comment, and just grabbed Grey's horn like it was the most natural thing in the world. The unicorn resisted, but they'd already been through this song and dance. It knew the prince would win in the end.
"I have a present for you," he went on, showing off the little gold cap. "We can't have you going around stabbing everyone, so I had this fashioned just for you."
"I'm honored," Grey growled, voice dripping with sarcasm. Casimir rolled his eyes but kept talking:
"I'm not a cruel man, Grey-"
"Ha! You're barely a man, boy."
Casimir's facade cracked, and he shoved the cap onto the unicorn's horn, harder then intended. This creature really knew how to press his buttons.
"I don't think you're one to talk," he said, tracing a finger down the unicorn's rump, landing on its pussy. He shoved the finger in, making Grey buck and arch its back in response, groaning loudly. Grey would've kicked him in the head, if not for the chains, and had to resort to thwacking him with its long bony tail. Cas, caught off guard, stumbled away from the beast, rubbing his cheek where it had connected.
"Careful or we're gonna crop that tail." All nonchalance had left his voice, which shook with a cold, controlled rage that amused the unicorn.
"I thought you said you weren't a cruel man."
"I'm not," Casimir said. "As long as you behave. Which is why, today, we will begin your training."
Grey groaned. "Let me guess, it's a sex thing."
"You're a quick learner," Casimir grinned.
"It's not like I have a choice. But first..." The unicorn's demeanor suddenly changed. Its voice sounded almost sincere. "Do you have a less bulky collar?"
"Why?" He wondered if this was some kind of trick.
"Much as I prefer my current form, being stuck as a quadruped is *stifling.* My people are shapeshifters by nature and this collar is way too big to fit on my human form."
Casimir raised his eyebrows. No book had ever mentioned unicorns being shapeshifters. He needed a second for it to sink in.
"I, uh... Sure. Yeah. I'll see if I can find another collar." Then he caught the lapse in character and straightened up. "I mean, yes. As a token of goodwill I will allow you to wear a more comfortable collar." He pretended not to hear the unicorn snickering.
Opening a chest by the wall, he dug through a treasure trove of harnesses, cuffs, spreaders, gags, and various other restraints before finding a collar that could fit both a human and a unicorn.
Grey closed its eyes when he fastened the collar around its throat and tied it to the cross ties. Then he unbuckled the heavy gold collar and threw it in the chest.
"Thank you," Grey said.
And before Casimir's eyes, the beast began to transform.
It was over in less than a minute, but that minute dragged out to a blissful eternity that Grey enjoyed beyond words.
It started with a tingle spreading all throughout its body. Heating up, blood rushing through its veins, face flushing red. Grey felt hot and tight, like something strained against its skin, fighting to break out, like a barely-contained full-body erection. The heat momentarily settled on its limbs, as thighs and upper arms lengthened, while hocks and pasterns began their journey into hands and feet.
It's cloven hooves split, two digits becoming four, with another fifth growing in, fingers buzzing with the anticipation of once again being able to jack off. The intense heat moved on to Grey's chest and back, where fur evaporated, replaced by soft pearlescent skin, and the beastly barrel-chest was replaced by defined pecs and back muscles.
Grey was panting now. It reached up to massage its pecs, at first hard, but soon covered by a plush layer of fat, just enough to give it something to play with. The heat moved from chest to head, as Grey's long, slender neck shrank down, just the right size for the collar Cas had picked out. Grey's panting became moaning. It was still playing with its soft little tits, but one hand reached up now to pull at the collar. It didn't budge and the unicorn's moans intensified.
It's long, equine jaw retracted, flat horse teeth becoming human incisors and canines. Eyes moved to the front of its face, remaining pale yellow and horizontally slitted, though no outsider would see it as the unicorn was currently rolling them back in sexual bliss. It bit its lip, nearing a frenzied ecstasy.
The heat moved back down, evaporating part of Grey's mane on the way, leaving the unicorn with just long white hair, hints of a beard, and a twisted ivory horn as remnants of its usual form.
As the heat settled on its rump and crotch, Grey gasped, lifting its tail, reaching down, frantically pulling at its cock and playing with its dripping pussy. The enormous cock and pussy seemed almost comical on the little human body. They barely changed, only shrinking slightly and rearranging themselves to better fit an upright posture.
Grey kept groping itself, pulling harder and faster at its cock, while the other hand frantically rubbed its wet clit and the little tits bounced, begging for someone to fondle them.
It overwhelmed the delicate creature. With an almost animalistic moan, it came from both genitals simultaneously, balls and pussy contracting, semen spurting into its hands and onto the floor, body wracked with the rhythmic throbbing of its vulva.
Grey collapsed into its afterglow, continuing to play with itself for a minute or two as the heat sizzled out, panting heavily and trying to recover its bearings.
Casimir, who hadn't been the one to inflict pleasure on the beast, silently wished he could feel even a fraction of Grey's pleasure. Instead, he just drank in the sight.
Grey was about his size, and entirely androgynous. It's soft breast-like chest had no nipples. Instead, the beast's udder had shifted slightly, one teat on each side of its sheath. They were round and fleshy, each about the size of a tangerine, with a large nipple standing proud.
Grey's cock was flaccid now and starting to retract into its sheath. Though smaller than it had been, it was still massive on a human body, about the length of Casimir's lower arm. And its balls were no less hefty, each the size of a goose egg. Only the beast's crotch, tail, chin, and head had remained covered in that glittering white fur. Everything else was smooth and pale.
Grey opened its eyes, face flushed and still panting, and turned to look at Casimir. The prince simply stared back.
Then he shrugged, trying to seem unfazed. "Not what I expected, but I can work with this." Might as well take this as an opportunity to see if unicorns had a refractory period.
Grey had barely recovered when the prince dragged it by the collar, away from the cross ties and onto the bed.
"Get on your hands and knees."
"I'm not doing that," the unicorn protested.
"I wasn't asking."
Grabbing the chains still around its ankles, Cas tied Grey's limbs to the bed posts. And just for good measure, he tied that pesky horn to two posts, just so the unicorn wouldn't get any ideas.
Seeing where the prince was going with this, Grey put its thighs together and lowered its tail, trying to cover up its holes.
He shook his head in mock disappointment. "Grey, Grey, Grey, I can't play with you like that. Do I really have to use force?"
The unicorn rolled its eyes. "More force than tying me to your bed?"
Cas just smiled, went back to the toy chest, and pulled out a leg spreader.
"This is not a punishment, Grey, I want you to know that," he said, while rigging the unicorn to the device. "It's just a fact of your life now. You can either resist and receive your actual punishment - or you can comply. And if you do that, who knows... I might even let you cum."
The unicorn, who had just orgasmed entirely on its own, wasn't tempted by that carrot. But it had been running from hounds since it could walk, and wasn't overly interested in seeing what kind of punishment this human might come up with. The prince, filthy creature that he was, was at least more creative than the hunters and farmers that the unicorn had been used to battling. Who knew what he might do?