"No, I'll be okay. I just nee.... eeigh!" Dave reached down to grasp the door handle, but instead his hand brushed against the staining cock between Amy's legs. She couldn't hold back any longer, and came. Thick globs of horse spunk drenched Dave's pants and torso.
Neither had much of a chance to reaction. After Amy came, another onslaught of changes assaulted her body. And meanwhile Dave's body started to bubble with changes. Although he couldn't see it, he felt a prickling as his moderately-sized dick and balls darkened considerable. His head thickened obscenely, resembling a cartoony tree more than a mushroom, before his shaft pulled into him like a fishing line. At the same time, Dave felt an ache inside of him, like an emptiness, as his balls both swelled into equine ovaries and forced themselves inside of him, creating a passage as they traveled. It was, the thought flitted across his mind, the weirdest erection of his life.
Despite the machinations happening beneath his cum-drenched clothing, however, Dave found he couldn't keep his eyes off Amy. She 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 more and more desire as Amy's body shifted before his eyes. "Amy," he said, his voice losing his normal assertiveness, "what is going on?"
Amy gave out an equine whiney, and Dave felt a rather uncomfortable warmth somewhere below. "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 looked down at the cum on his clothes with a strange mixture of disgust and (if he thought about it for a second) arousal. "It's okay, it's okay," he said, distracted, wiping a swab on his shirt with his index finger - which tingled. Dave's eyes traveled up, lingering on the... thick... big cock now softening out the front of Amy's bathrobe. "People don't just grow horse cocks and get fur overnight for no reason. There has to be an explanation for this," Dave said softly, his eyes finally meeting her confused (handsome?) face.
"Well, what should we do now then?" Amy asked.