After Mike dismounted from Jenny, she got up and walked over to where the pills were. She smiled a little as she looked back at you as you sat back on your haunches and wagged your tail. Your mistress was so good to you, what was she going to do next? The idea excited you as you waited for some sort of answer.
"Let's see, what to pick..." Jenny said as she sorted through the pills for a long moment. She had to admit that this excited her more than anything as the mixed juices leaked out of her pussy, besides it wasn't like she was going to be a dog permanently right? She wanted to experience this fully with Mike, and the idea excited her more than it should.
She finally picked out two pills, a pink one and a black one. She got some water and quickly swallowed them as she walked back to Mike and bent down and kissed him on the head. "Let's have some fun boy, are you ready to fuck another bitch?"
Mike's ears perked up at that suggestion and he breathed in deeply as the scent of a bitch in heat reached his nostrils. Jenny turned around and moved onto all fours as black fur started to grow along her body as she smirked back at Mike. "Fuck me, take me like the bitch I want to be..."
Mike pushed his muzzle in close and sniffed in deep as he took in her changing scent. His doggy instincts triggered as he registered her as a bitch in heat and his cock slipped out of its sheath. He barked happily as he was excited at the prospect and mounted him, and without hesitation thrust into Jenny's pussy.
Jenny let out a moan as the pure animalistic feeling of being mounted by her transformed boyfriend. She was horny and she wanted to be fucked by this dog as she felt the red rocket being shoved into her. She moaned loudly as she felt his knot starting to press against her transforming pussy.
She let out a long moan that turned into a howl as her face pushed out into a dog muzzle. Her body was now covered with black fur as her tail sprouted out of her butt and her ears became floppy. She barked loudly as her human mind slipped, now completely consumed by the mind of the dog as he thrust his knot into her, locking the two of them together as she whined a little.
There was nothing left of the two humans as the house was filled with the yips and barks of the mating dogs. Finally, Mike thrust into her one last time and they howled together as he came hard, filling the black lab bitch with his seed. The now completely canine Jenny wagged her tail a little as they waited for Mike's knot to deflate.
When it finally deflated Mike looked around confused for a moment at the absence of his mistress. There was only this beautiful bitch that smelled so good, despite having just finished he wanted to mate her again, to make sure that she was pregnant with his pups. She certainly seemed receptive as she pushed her butt up and barked again.
It was time for round two.