How do you know a guy finds you sexually attractive?
Eyes: If he gives you a piercing look or looks you in the eyes longer than most people do. Eyebrow flashes might also indicate he feels attracted.
Shoulders: If he straightens his back to look taller and broad shouldered.
Chest: If he expands his chest and holds in his stomach.
Mouth: Smiling is an important part of flirting.
Voice: If he talks in lower, more seductive voice. Joking around is also often used by guys.
Arms: If his arms form no barrier between you and her.
Hands: If he puts his thumbs in his pockets or behind his belt, pointing his fingers to his genitals. Any body posture that makes him look tough, like leaning his body casually against the wall, is a way of flirting.
Lower part of his body: Any posture in which he comes forward with his groin. Normally this happens without the guy realising it.
Legs: If he stands in such a way that attention is focussed on the groin, for instance sitting or standing with his legs apart.