"What the hell?!" Dave exclaimed loudly. Amy could only babble in response as changes swept across her body. Fur began sprouting up around her crotch, spreading down her legs and up towards her modest breasts, stopping only a few inches before them. Her legs began to change as well, her nails darkening to a deep black and growing more muscular. Finally, her tail grew to bigger proportions, the hairs growing down to her knees.
Dave watched in a mix of horror and fascination, and a little bit of desire as Amy's body shifted before his eyes. "Amy, what's going on?" He questioned assertively. He looked down at his newly improved male member, which had since grown past the top of his pants and was plainly visible in front of his shirt. It was a dark brown, almost black color with splotches of pink that mottled its surface. The head had become blunt and flared, and his urethra had shifted from the center towards the front of his horsecock.
"I don't know! I just woke up this morning this this... thing between my legs and that's all I know!" Amy wailed in desperation as she inspected her newest changes. "And apparently every time I cum, I change more." She finished. Dave shook his head in disbelief. "Well, what caused it? People just don't start turning into horses-" "Don't say that!" Amy interrupted. "Don't say that please, I don't want to be a horse!" She sobbed, almost on the verge of tears now. "Okay then, people don't just grow horse cocks and get fur overnight for no reason. There has to be an explanation for this." Dave replied, and put his arm around Amy's shoulder try to comfort her.
"Well, what should we do now then?" Amy asked.