"Mike! I didn't mean for..." Timmy's explanation broke off as he realized all that was coming out of his mouth were whines, like those of a dog! He tried to clear his throat and made a woofing noise. Mike jumped over the fence and squatted down beside him as Sampson continued to push in.
"Fuck, man! You're turning into a dog!" Mike's eyes widene4d as he realized Timmy wasn't just playing around with the Great Dane. His eyes widened and he looked bewildered at first, but then grinned and watched in amazement. "Holy shit! How are you doing this?"
Timmy couldn't answer - not only because he could no longer talk, but because the sensations from his cunt were starting to create new instincts and needs in his head. A growing part of him was accepting Samson as a mate, and thought the fading human parts of his body were the wrong things. No! He struggled against the canine mentality. He was human, a boy with a future ahead of him!
He saw Mike reach under his belly and then felt pressure on his shrinking cock. "Man, you are putting out a shitload of cum!" His friend's fingers rubbed what was left of Timmy's testicles, sending even more intense sensations through his body. He felt his penis shrink as it spurted the last semen from vanishing balls, and heard Mike laugh as he masturbated the remnants of Timmy's manhood away. Timmy was confused - why was Mike helping take away his humanity? Or was Mike helping him regain his doghood?
Samson pounded even harder, his knot locking him inside Timmy as he continued to pump. The sensations were overwhelming, a powerful pain/pleasure that was also doing strange things to his brain. Mike was rubbing the nub of a female Great Dane now, grinning as he watched Timmy rapidly finish changing. Timmy was only dimly aware of his hands closing up, his back end shifting as his legs became those of a dog, and a gradual lengthening of his... her neck. She could smell Sampson now, a powerful male scent that spoke to her instincts. She also smelled the human - Mike - male, but not in a way that would excite her. There was a different smell from him as well, something that appealed to her.
"Whoa. I feel weird." Mike sat down on the ground beside the still-mating dogs. His scent was changing quickly, becoming more like that of Sampson, but not as a mate. "What's happening to me?" His voice cracked, shifting higher. Timmy twisted back and dimly recognized the young boy as the Mikey he had gone to grade school with, clothing falling off a shrinking body. "No! Don't wanna be little!" Already no more than 7, Mike struggled to get up, but got tangled in the oversized clothing and fell again. By the time he pushed up again, he was 5, and losing age rapidly. His scent was very different now, and Timmy recognized it now. Great Dane, but not like the mature scent of Sampson or even his own strong female scent. Mike was getting younger, smaller, less defined. Though nothing was visible, Timmy felt things happening inside her womb. Mike was a pulsing white mass now, dwindling incredibly fast, no longer a human. Just before the tiny spot of dampness vanished, Timmy felt a corresponding presence inside her - Mike was now a mas of eggs within her body. And just then Sampson finally let go with his seed to fertilize some of the many eggs that had been Mike.