Eric was dumbfounded. He couldn't believe what he was hearing and seeing. He'd never thought some kinky fun with the Chronivac would turn into this, would leave his girlfriend a sex-crazed creature so depraved that she wanted to turn him into a ratgirl like her and take turns fucking his own pet rat forever.
Maybe he could use the sex-crazed part to his advantage, though.
Eric stood up and moved over to Lisa. She looked up at him quizzically. God, he thought, I'm almost a head taller than her now. I might be able to take charge of this situation yet.
He bent and jammed two fingers into her pussy like he was gripping a bowling ball. The shock made her jaw drop and she let out a high-pitched squeal. Eric leaned in toward her rodent ear. "You mentioned fingering each other," he murmured. "What's stopping us from doing that now?"
Internally, he found himself wanting to recoil in disgust. This close to her, she smelled like a mix of his rat's cage and bestial sex, and her vagina was practically weeping. He'd been in there before, and it still felt like Lisa, but now it was different...bigger, stranger somehow. And ringed with sopping fur. He was sure some of the warm fluids washing over his hand weren't hers. But Eric did his best to put those thoughts out of his head, and pumped his fingers in and out of his girlfriend, which seemed to be working.
"Hahh...hahhh...E-Eric...hahh...oh, Eric..." she breathed in pleasure. Trembling, she reached for his other hand with hers until she found it, and led him toward her breast -- in the process brushing up against some of her thick teats, which almost made him lose his nerve, but he reached his destination and began working her nipple as well. Nuzzling her fuzzy neck, he slowly maneuvered the two of them near his bed, where Lisa dropped off Tomtom so she could rub her clit.
Eric wasn't sure where he was going with this, other than convincing her that he was still there for her. And...damn it, in spite of it all, he found himself becoming aroused by the little squeaks she was making. She may have become a rat-thing, but she was still his girlfriend. When he closed his eyes he could picture the sexy body she used to have, and his cock began to rise.
...His horse cock! He kept forgetting he'd modified it with the Chronivac until it started to get in the way. He'd masturbated with it once, but hadn't really gotten a chance to use it as he was hoping to. It was tenting his pants rather painfully, so he abandoned Lisa's breast to undo his button and zipper. He lowered his pants and underwear one-handed, freeing his massive dong, which promptly slapped Lisa in the thigh.
"Ooh! What was that?" she said, breaking out of her trance. She looked down at the mottled thing jabbing her and laughed. "Ok, wait, this guy has got to go." Eric kicked himself mentally. Whatever moment they'd been sharing, it had passed. She smacked at his hand until he regretfully slipped it out of her, and she sauntered over to the Chronivac, typing with one hand while still furiously kneading her clit with the other.
Eric discovered his dick was shrinking, and not just because fun sexy time was over. The flat head puffed out into a more human shape, the medial ring smoothed out, and its uniform pink coloration returned as his penis drooped and retreated, 8 inches, 6 inches, 5 inches...wait, was it going to stop? Lisa had mentioned giving him a pussy...