I'm not a guy but in silly ass movies you're suppose to make a move.
With women, they flip their hair and ask about yourself (not all the time but more times than their friends or family). They may just be wanting to vent or make friends. I think however it's when they start touching you, since I know I've been hit on, you start realizing. They touch your arm and make intense eye contact that leaves you either scared or willing. But be careful, don't take this as a "I want you thing". Try to be "like a friend" or understading and let them lead you on. This is however noway an expert advice. Many many people would disagree with me. Be very careful only because many of us aspies tend to take love or "lust" a little too serious.
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I live as I choose or I will not live at all.
~Delores O’Riordan