Will woke up dazed, his head felt weird, holding his hand to his head he got out of bed and held it for a moment. Once the headache subsided he sighed. Will looked around at the cabin, he had unpacked earlier, so he assumed that it was just feeling a little homesick from his old house.
Shaking his head Will walked towards the kitchen, past Al's terrarium. Al lifted his head up and Will felt butterflies in his stomach for some reason. Keeping his eyes off Al he walked into the kitchen, making himself a bowl of cereal for breakfest. Sitting down Will should have noticed a slight feeling, or rather the lack of one from his crotch. Normally he would feel himself sitting down with his penis along with his butt, but he didn't notice it.
In Will's pants his penis had shriveled, along with his balls, shrinking slowly without his notice. As his testicales retreated inside him a horizontal slit had devolving from his ballsack, his tiny penis shriveling into it's new home. Will did not possess vagina, but rather a snake's cloaca. The new lack of a package caused Will's pants to loosen as he finished eating, standing up he noticed the loose feeling of his pants, but not the lack of his penis.
Walking into the bathroom will pulled down his pants and underwear without looking and started pushing to piss. But it didn't come. Bored Will looked down and instantly his eyes widened, and he screamed. His penis was gone and in it's place was what he thought was a vagina.
Al poked his head up at Will's scream and gave a small Snakey grin. Before lifting the top of his terrarium up and slithering out towards the bathroom. Inside Will was having a panic attack as he sat down on the toilet. Trying not to look at his lack of maleness he walked outside the bathroom without his pants or underwear to go get new ones.
Al was waiting just outside the door, the snake slithering up Will's leg and pushing him down to the floor. Will fell back with a bump, hitting his head on the floor and dazing him. Al noticed this daze and worked to get Will's shirt off him. Once he got it off he slithered on top of Will. The dazed man looking up and seeing his pet snake on top of him. At Al's end his hemipenes were above Will's cloaca. Forcing himself on Will he pushed his forked tounge into Will's mouth, kissing the man who shocked, kissed back.
The butterflies had returned to Will as he kissed Al. The snake lowering his hemipenes into Will's cloaca. Will instantly felt the penetration, and it was the best feeling he had ever had. Dealing the kiss he thrust his hip to lodge himself further on Al's hemipenes, wrapping his arms around Al as he felt a hotness in his cloaca.
Al let loose his load into Will, who yelled in pleasure before passing out, the juices of Al's semen mixing with his... Her new cloaca. Her body absorbed the semen, already starting her next change. As Al stood guard over her.