Little sis wakes up to big brother jerking off to her and reminds him what she's told him in the past-- "if you want to get off to me, just let me know! You don't have to hide it, I find it really hot." The situation turns into some intense jerk off instruction / jerk off encouragement and she becomes increasingly more desperate for your cock. She really wants you to fuck her! By the end of it she's begging you to stuff your cock inside her young pussy and fill her with your seed!