Your new step-sister finds out you've been jerking off to her pictures! She threatens to tell on you, but you say you'll do anything if she keeps her mouth shut. Absolutely ANYTHING. She thinks of a really gross task for you, if you pull your little dick and jerk off in front of her before eating ALL of your cum, then she won't tell on you... you don't really have much of a choice. As you are cleaning up your own cum with your tongue, she laughs, and takes your allowance on top of it.