Lexie's skin is pleasantly soft under your fingers, under your tongue. You shouldn't be thinking that. You shouldn't know that.
You blame your traumatic childhood. Obviously your absent father and your crappy mother have left you seriously warped. You've made plenty of bad sexual decisions but having sex with your half-sister while your roommates are asleep down the hall is possibly the worst decision you've made to date.
Then you think that maybe growing up with your father and a non-psychotic mother wouldn't have helped because, when you run your tongue along the inside of her thigh, Lexie lets out a moan that indicates she's enjoying this just as much as you are and, really, what's her excuse?
"This is twisted," you say as she lifts her hips and parts her legs just a little farther.
"Yeah," she agrees.
But she doesn't say anything else so you move your tongue to her clit. You aren't great at talking to Lexie anyway. She moans as your tongue circles her clit.
Lexie lets out a disappointed sigh when you eventually stop. But you work your way up her body and, when your face is just inches from hers and she's looking right at you, you slide two fingers inside her. You're surprised at how turned on you are at the way her lips part slightly as she looks up at you.
You position your thumb so it strokes her clit with each thrust of your fingers. She raises her hips to eagerly arch against your touch.
Your fingers move slowly at first. You speed up as Lexie's movements beneath you become more frantic, more needy.
Finally, she gasps and you feel her tighten around you. You curl your fingers slightly inside her.
She shudders and says your name as she comes.
Lexie reaches up and trails her fingers along the side of your face. You lean down and brush your lips against hers.
Now you know you're warped because it occurs to you that this is the first time you've felt affection for your sister since you met her.