Barney Stinson rules

1. If she tells you she's "married."
This is chick-code for "I haven't done it in months, take me now."

2. If you're blocking her path to the bathroom and she says, "Pardon me."
Take away the P, A, R, and N and you have "Do me." It doesn't get much clearer than that. She wants you to join her in stall #3.

3. If she slaps you.
You know what they say: any physical contact is good contact. Be sure to establish a "safe word" beforehand. I recommend "help!"