After some thought, Steve decided that he wanted to try being a dog. He had always wondered why they were so happy and carefree, so without hesitation, he pressed the link that would make him a full canine hybrid.
After a few seconds, he found himself dropping to all fours. His legs were beginning to bend back, feet shrinking as the toenails became sharp and claw-like, the skin turning into sensitive pads. His hands were shrinking too; the middle fingers on both vanished and he had four long stubs with claws and pads instead. Hair began to sprout on his legs and spread upwards until he had a fine coat of it covering every inch of his skin. His spine burst out through his backside, giving him a long furry tail to wag.
Suddenly, the transformation briefly stopped, giving Steve the chance to res tout his new body. He found that he could switch from standing on two legs to four at a minute's notice, and could move faster and jump slightly higher. He was so distracted by his newfound enjoyment that he didn't notice the two flaps of skin forming where his ears had once been, or his face beginning to stretch out into a muzzle, or his teeth becoming sharp and pointy. Not until a double blast of heavily enhanced smell and sound came blasting through his skull did he realize what had happened.
But there was still one major change in store. Steve sat up as he noticed his penis beginning to change. It turned as bright pink as bubblegum, before vanishing under a thick layer of dark foreskin. Steve remembered reading up on this back when he had be forced to take care of a friend's dog once. Canine dicks only emerged from their foreskin when the dog was aroused, and when inserted, the tip would inflate (a "knot", or something like that), allowing the cock to stay inside a female until the poor mutt had released his semen. Steve was eager to try this out, but first he wanted to spend some time outdoors, maybe even find out what it was like to use the bathroom like a dog. Good thing his parents had left the back door slightly open.