As you walk into the bathroom and stand in front of the toilet, you sigh in relief and pull down your pants and start going pee. It felt so good...but almost too good. You suddenly find yourself racked with a burning pleasure in your groin, and you begin moaning.
"Uhhhhhh...what's going on?" You look down at your groin and see in horror that it's becoming motted, being different shades of brown and white and a little pink. You reach down and touch it and get a shock of pleasure, and you then watch as your head becomes much pointer...almost like a horse cock.
" Oh my god!" You suddenly scream out...that dream was right. You tried to think it over more, but there were still more changes. You then watched as around your belly button and your stomach a thick, dense, patch of fur developed...a sheath. Your cock had also gotten much...much bigger. It had dropped down to your knees and gotten as thick as a beer can. It seemed as if you really did have that prime race horse cock. You then watched in horror as your new horse cock shot out in huge torrents the last of your piss and then retracted back into your new sheath. It seemed as if it was all over...for now.
You looked at yourself and realized how absurd you looked. On your otherwise human, hairless body was a massive, hairy sheath with a fat pink cock sticking out. You sat there for a moment next...deciding what to do.