Number 3

She gets close to a friend on the dance floor

Two girls grinding on the dance floor is a lot like wrestling: Even though you know it's all fake, you still can't help but like it. It doesn't take a study by Kinsey to figure out why men are blown away by this sight. Sweaty, drunk girls groping each other, the air charged with sexual energy ‑- and it's not even happening on DVD! Inevitably, some doughhead will ruin it for everyone by trying to sneak into the middle, but can you really blame him?

Number 2

She gives a sneak peek at the goods

Men are very easily visually aroused -- that's why porn is a multi-billion-dollar industry. So catching an unintended glimpse of a girl's "unmentionables" immediately gets the hormones flowing. Catching a peek at a lacy thong or watching the seductive trip of a dress strap as it fortuitously slips off a shoulder can do more for the libido than the raunchiest full frontal ever could.

Number 1

She suggests watching something dirty

Most men aren't particularly proud of their porn obsession (pornographers are just so good at marketing it to us!). So it goes without saying that having a girl suggest a "blue movie" is as big a relief as it is a turn-on. Who doesn't get charged up watching beautiful professionals pleasuring each other while doing some pleasuring of their own? Dirty flicks also provide lots of great ideas and suggestions (along with a bit of penis envy) and can keep things super-steamy for hours. Bonus: You can watch her searching for the right movie at the store for a glimpse into those closet ideas she isn't quite ready to reveal yet.