Fur sprouted on Colin's skin as he started to become a stud dog. He'd raised his heterosexual tendancies to 100%, set his sperm production limits to maximum, increased his canine stamina, and increased his canine mind to 50%. His human mind would remember, but he'd be dog enough to do the job required.
He slipped out of his clothes, and giggled as he saw his foreskin developing. Suddenly, he inhaled a heady musky scent. Bitches in heat!
His conical red canine cock popped out of its furry shealth, as Colin dropped to all fours. The colors drained from his room, but a new pallet of mental colors-scents filled his mind.
He and his friends circled sniffed butt, and then he mounted Rob, and after about 20 minutes his knot released and he mounted Bryan. Then he repeated his actions mounting Rob and Bryan again to make sure. It was while he sat on his bed licking his doggy cock that Colin caught scent of another bitch in heat. He went to the open window and slipped out. The Chronivac timer counted down 15 minutes to reversion.
Burrowing under the neighbor's fence, Colin the dog stud mounted his neighbor's 5 year old bitch. Part of his mind said no that the mutts he'd father would be butt ugly, but the canine part of his brain was in control. He knotted.
BING!
Colin's canine hearing heard the Chronivac chime back in his house. Oh, no! He was going to change back. He tried to pull out, but his cock was firmly knotted. His bare skin returned in sharp contrast to the hairy beast he had mounted, but he was still knotted!
Then he heard voices approaching, and he was still half human-half dog.