Four Legged Fun

Suddenly Jon felt himself shrink and fall upon something furry. His vision also seemed to shift and he was no longer seeing color in the same way but more in black and white shades. Even worse he seemed to suddenly be standing on four legs!
He turned at the growl of something immediately behind him and got ready to respond when a strange scent hit his nostrils He saw another dog in front of him (now realizing that he was also dog) and somthing about its scent caused his legs to stiffen. The other dog sniffed at his crotch and butt and he responded somehow automatically by sniffing at the other dogs penis. A wave of strange desire came over him.
When the other dog moved around behind him and Jon found himself unable to move he knew he was in BIG trouble...