Vaginal Sex

You're eyeing your sister's bare leg and thigh behind her with unbrotherly desire... "I want to lose my virginity. Let me fuck you first, and then you can have my balls." You offer- ... at which your sister almost flinches, but to your surprise, she doesn't look disgusted.

But she seems unsure, and still holds on to your balls. "Seriously? Would you be wearing a condom?" She asks warily with two eyes affixed intently on your own. You're angered by her question. "Only if you leave my nuts alone! I'm losing a lot in this deal." You rebuke; her fingertips shift across your balls, and you watch her shoulders shrug and roll...