Fuck your sister senseless

You kiss her hard while forcing your tongue into her mouth as you start thrusting against her. She keeps making protesting noises as you do this, but you muffle them easily enough so your mother won't hear anything from downstairs. You keep raising and lowering your hips, working your cock in and out of her box. She struggles feebly as you continue to fuck her but her pussy seems to be enjoying the attention even though she knew it was wrong, growing wet and slippery even while she's fighting you.

You soon find yourself breathing heavily and have to break the kiss to catch your breath. She's gasping for breath and unable to shout their mother as you continue to thrust into her.

"Brandon...," she says as she looks away, unable to meet you in the eyes. "Please. If you... have to do this... Please don't cum inside me... Don't make me pregnant... Please..."

Her vaginal walls spasm around your cock, then clench up tight. She's climaxing in spite of herself. She squeezes her eyes shut and her face flushes with pleasure. The feel of her orgasming around you is too much for you.