I forget where I got this from, maybe Adam Lyons... but it's good. I sort of changed it up to suit myself:
Ask them to play the question game. Tell them all they have to do is answer every question honestly, and the first one to pussy out of answering has to buy the other a drink (or something similar) - you can also tease about how they can't handle it or how they've got an unfair advantage cause they seem like the innocent type and probably don't have any shocking answers to give etc...
Gradually bring sex into it (though she probably will anyway) have your questions as something like this:
1.) What's the weirdest thing you've ever eaten?
2.) What's the most embarrassing thing you've ever done while you've been drunk?
3.) How old were you when you had your first kiss?
4.) What is your biggest turn off?
5.) What is your biggest turn on? (The last question sets you up for this one to not be so weird)
I don't think I've explained this great... but judging by your post, you're experienced enough to use the general idea and understand where I'm coming from.
Hope I helped
