...but why does it turn you on?

"Mmm, you're looking so cute every time you roll this little slut's nipple in your tongue~ Come here, I need some time with you."

They pull away, and yep, they're kissing each other. With tongues, and lips running all over each other's faces. And holding tight on to each other's hips. There's no doubt about it. There's nothing chaste about what these two twin sisters, related by blood, feel for each other, even to the extent that they're willing to express it right in front of you. Everything tells you this is wrong, that they can't possibly do this, but your body has begun to override your brain. This, it tells you, is hot.

And you begin to fantasise. About being in between them, the object of both their affections. About having a big sister of your own (definitely a big sister), who cares for you as much as these two care for each other. And you moan and squirm again. Lacie seems to notice this, as she turns away from her incestuous embrace and glares at you.

"What's that, Lacie? Ooh, it looks like someone's even hornier! Guess seeing what sisters really do behind closed doors is too much for you, huh? You're a dirty girl. A dirty, slutty girl."

"I like her." Lacie speaks up on her own for once, though never raising her tone. "We should keep her."

"Good idea, baby sis~ Don't worry, we'll get back into it in our dorm..." That'll be an image that's seared into your brain, for sure. "But right now, let's give our new pet a super special reward, huh?"

Lacie seems to have an interesting interpretation of what a "special reward" is, as she gets right on her knees, retrieves your panties, and clamps them over your cock, the crotch of them sitting right on your dripping head, mingling the previous wet spot of pre-cum with another.

Meanwhile, Gracie gets in front of you and turns around, giving you a very good view of her rear. "You like this, huh? You like my big fat ass? You liked it last week, you took me hard from behind, making the cheeks clap, digging your cute, whore hips into them~ Now, use your words. Tell me you like my ass, or I'll leave you here with your sad, dripping dick out for anyone to find you."

As much as the idea of being left here at the mercy of any other woman seems not too bad when you think about it, the natural instinct is to blindly obey. You can just barely **** it out. "I-I love it... I-I love... your ass..."

"Good, good girl~ Now come for it." And so she begins to shake it, that bountiful behind making all the moves it can. Once again, it's making the moves it did on that evening. Each jiggle, each roll, each shake accentuating the shape and the softness and the sheer size of it. Time seems to slow down as she performs this raw, erotic dance right in front of you.

And then Lacie begins to jerk roughly at your member, and it takes mere seconds before you obey her sister's command. Your spine seems to curl and crumple on its own as you whimper and whine and spurt a long-pent-up load of fluids all over the underwear fabric restraining your tip. Your mind goes blank. You see nothing but Gracie taunting you with her backside, you hear nothing but your own moans of climax, and the only sensation you feel is that exuding from the head of your cock, shooting through your body just as it's shooting outward.

You barely feel yourself fading in before Lacie extracts your dirty garment from your genitals and displays it to you.

"Ooh, look. This cute little bitch is so horny she came right in her panties~" Gracie speaks up. "Did we do that to her? No one's that sex-addicted, surely? Oh well. We've got her now. We've got to deal with her kinks. Did you see, she's turned on by when we kiss! Maybe she wants to be a third sister? The useless one, who we use for whatever we need?"

Lacie lays your cum-soaked underwear down with your skirt, as the two girls begin to re-dress. Quite unlike their stripping, it's quick and efficient. It's not long at all before they're fully clothed, as if they haven't just sexually tormented you. Lacie scribbles something on to a piece of paper, and stuffs it, crumpled, into your hand while Gracie is untying it. You let out a little sigh as you're freed.

"Bye~ Make sure you get dressed before some brainless cunt gets her eyes on you!" Gracie waves, her voice dripping with venom as always, as she and Lacie take their leave.

So now it's just you. You're too exhausted to re-don your clothes, even despite Gracie's warning that someone else might arrive, and besides, your panties are a lost cause anyway. So, you slump yourself back against the radiator. You've got a lot of considering to do about what just happened. The main issue being how you had no control, you were treated like garbage, and yet you loved it so much. You can't help but contrast it with the worst times you had being the ones where you were taking the initiative - Gracie the first time, and Seraphine. Could it be... you like to be used? To be bullied? That could be something to explore.

You take a look at the piece of paper. On it is a pair of phone numbers, and the note: If we call you, YOU ARE THERE. You don't feel like you'd complain if they did call.