Play innocent and see what happens.
From Create Your Own Story
"I'm sorry Kara, I have no idea what you're talking about," you say as calmly as you can muster. Kara then backs away a little and smiles, saying "Really? So if I was to cop a feel right now, you wouldn't be erect? Or if I was to take my shirt off you wouldn't want to grope me?" You think to yourself that your innocent idea didn't work so well, but you don't want to admit she's right because you're a competitive fucker.
In a semi-shocked tone you respond, "Well, if you took off your shirt Kara I would obviously be tempted to touch them. But you're Adam's younger sister, so I just don't think I could do something like that." The edges of your voice are giving away your tease, laced with playful desire.
Kara doesn't seem to totally grasp your flirtatiousness though, and says in a higher tone, "Cut the bullshit. I know what I felt when I was on your lap, I heard the stories, and I'm taking a sex education class this semester, so put the pieces together and I turned you on, so admit it!" Her cute, flushed face is pinched up a little with frustration.
Do you: