"Without even thinking about it, women almost always give physical tips that convey their level of interest in a man. The most common body language gestures that reveal at least minimal interest are hair twirling, hair tossing and leg crossing. When a woman tosses her hair, it comes across as a nervous gesture. What it tells the man is, he's making her a bit nervous. And to his mind, if she's nervous, she must be interested!
On the other hand, hair tossing, like leg crossing, is also a preening gesture. It's a way of calling attention or showing off a gorgeous, glossy mane (very sexy) or a terrific pair of gams (ditto, also very sexy!). But there are many other elemental gestures and basic postures that send a strong message to another person, all of which can be used to good effect"
Body language between Kirsten Dunst and Jake Gyllenhaal.
Jake is a little more grown-up now he is dating Reese Witherspoon: