Your gf Lisa is a Lamia, its a pretty normal relationship despite the tail and constricting.

It’s the middle of the night and you wake up to find Lisa coiled around you with your head smushed against her chest. As you squirm you hear her groan, waking up slightly

“Babe, quit squirming and just go back to sleep. I know i’m kinda constricting you but it’s cold and im coldblooded, gotta get my heat from somewhere.”

As you keep squirming, you feel her tighten her coils, squeezing you tighter than before

“Quit. You understand that i need your bodyheat, and your squirming reminds me of a mouse right now. You know what happens when i get a mouse in my coils, right?”

As you keep squirming she leans down to your ear, squeezing you tighter

“I bite. And you know i have enough venom in these fangs to put you to sleep for two days at most. So unless you want to take a prolonged nap, i suggest you stay still, and go to sleep.”