私は彼女を彼女の新しいボーイフレンドと外出させるのと引き換えに私の義理の妹のお尻をファックします。

My stepsister asks me for permission to let her go see her boyfriend, I'm jealous of her because she's the only one who can have sex with me, so I tell her that I'm letting her out in exchange for me making me cum in her ass, which she agrees to and earns permission.