On a 7-9, Madison lets you fuck her, if you turn her on

Madison arches her back as Taylor sucks her nipple. "Touch me, Tom, and make me want you."

You put one of your hands on top of each of Madison's hand and help her grope herself. You squeeze her boob, using her own hand, and then you make her rub her own clit with her other thumb. She gasps, looking you deep in the eyes, a look of wanton need on her face. Then you move her hands aside and grope her yourself, squeezing hard on her tit and pinching her nipple, while also slipping two fingers inside her. You thrust forward with your hips, bouncing off your hand in her cunt. You bump your digits deeper into her pussy with each movement. Madison gasps with each deeper thrust of fingers inside her. Then you lean down and take her nipple into your mouth, sucking it hard. Madison shrieks pretty loudly, since Taylor also sucks harder on the nipple on her side.

After about the dozenth thrust of your hips, Madison's groan goes up the octave until she hits a high-C, and her body trembles through another big climax. "Oh, God. Oh, God! Yes, Tom! Fill me up!" she shouts, her small tits jiggling as her body shakes.

She grabs your johnson and guides you toward her weeping slit. You step closer, as she rubs your mushroom head on her clit.

"Give me your cock, Tom. I don't care that you're my brother. It's such a beautiful cock."

You fit the head inside her, and then hold her hip, while you run the other hand up her belly to her boob, squeezing it and pinching the nipple. When she groans again, you push forward with your hips, burying your tool inside your sister. Her body accepts your length easily, and you bottom out, pubes to pubes.

You start thrusting with your hips, colliding with her groin.