Blackmail her over the shaved pussy
From Create Your Own Story
"You shaved your pussy, Callie?" You ask her smugly.
She blushes. "Some of the girls in the magazine didn't have any hair... I just thought I would give it a try." She looks at you nervously. "Don't tell mom and dad about this, please."
"Why shouldn't I, Callie?" You look at her seriously.
Callie's eyes widen. "Because you know them! They would get mad at me about this! I'd get the belt and be grounded..."
Callie is obviously worried about you telling your parents. Now to use it to your advantage. "What will you do for me if I promise not to them them about this?"
Now Callie looks a little worried about you. "You're already seen me naked... what else did you have in mind?" She drops her eyes. "Despite my... sins... I am still a good girl. I'm not lying with you, like a husband with his wife, if that's what you're looking for. I've saving that for marriage."
That was what you were thinking of, although Callie seems opposed to it as a result of her religiousness. You could press the issue of sex with her, and see how badly she wants to keep her secrets, or see if she is willing to agree to something that lets her keep her virginity... for now. Or you could just force yourself on her, and use what you know about her to buy her silence.
What do you do next?