Forget being a "sexpert" - the minute anyone finds out Tracey Cox, a relationship expert, also specialises in body language, sex questions get shoved aside.
"This is what most people want to know when they corner me at parties - 'how do I tell when someone fancies me?'," she reveals.
Well, we all know about hair flicking and licking of lips, but Cox told the Daily Mail some of the other important but subtle signs to look out for...
1. He's given you three looks in quick succession
The first is a 'stranger look' - he's checking you out because you're a human being who's passed into his line of vision.
He looks a second time simply because he's clocked you're female.
Now, pay attention, because if he fancies you, he'll look back a third time.
Even better if he darts the three looks while he's five or six feet away.
2. He pulls his socks up
I swear I'm not making it up!
This one harks back to the days when men only dressed up on special occasions and teamed tired old socks with their ill-fitting suits, so spent half the night pulling them up to complete the (usually dreadful anyway) look.
It's a gesture that's become second nature: if he pulls his socks up or adjusts them in your divine presence, it's an almost a 100% guaranteed sign he's trying to look his best and is interested.
3. He's pointing to his genitals - literally!
If he puts his hands on his hips with his fingers splayed and pointing down toward you-know-what, he's subconsciously willing you to look at it.
He'll also spread his legs when sitting opposite you, to give you a full display of his crotch. Hopefully he's still got his clothes on at the time.
4. His feet point toward you
If we find someone attractive, we point at them subconsciously with our hands, arms, feet, legs and toes.
Check out the feet next time you spot a group of men with a particularly attractive women among them.
Even if they are pretending not to notice by chatting lovingly to their girlfriends, their feet give them away: inevitably, they're all pointing in her direction.
5. He's touching his face often, especially as he looks at you
If he's keen, he'll stroke his cheek up and down with the back of his fingers, touch his ears or rub his chin.
It's a combination of nervous excitement, preening (smoothing clothes or eyebrows or hair to make sure he looks OK) and autoerotic touching (more on that delicious topic later).
6. His eyes move in a triangle
When we look at people we're not close to, our eyes make a zig-zag motion: we look from eye to eye but also look down to include the nose and mouth.
Once we start flirting, the triangle gets even bigger.
We spend more time looking at their mouth and the triangle widens at the bottom to include the good bits (like breasts and crotch).
It starts with the flirting triangle and becomes more intense as the flirting intensifies.
7. He's looking at your mouth loads
The more infatuated he is, the more time he'll spend looking at your mouth while you're talking.
It's a very, very sexy gesture because you can't help but think: "I wonder if he's imagining what it would be like to kiss me?"
Which is exactly what he is thinking. Among other things.
8. He's blinking a lot
If someone likes what they see, their pupils dilate and their blink rate increases.
If you want to up the odds in your favour, try increasing the blink rate of the person you're talking to by blinking more yourself.
If the person likes you, they'll unconsciously try to match your blink rate to keep in sync with you, which in turn, makes you both feel more attracted to each other.
9. He's 'blocking' your space
It's officially called blocking: using your body to create private space and establish a boundary around you and the person you fancy.
Men often block by putting one hand up again the wall behind you, leaving you (rather effectively) trapped underneath his armpit (and yes, start praying he reached for more than just his toothbrush that morning).
Another (sweeter) way he'll block is to lean his head close to yours to create your own little vacuum in a crowded room.
10. He keeps squeezing his bottle or can of beer
When men are sexually interested in someone, they start playing with circular objects.
No real prizes for guessing why: circular objects remind him of your breasts (no, never!) and his body is telling what's happening in his subconscious mind.