This person will constantly alter which gender they are more attracted to.
Often they will appear to be very androgynous, and hang out with the scene crowd.
Isn't Flirt Boy just doing what women have done for hundreds of years?
Teasing is one of the things men and women differ in; men can tease you by pulling your hair, but women tease on a much more visceral level, right down to the loins. If we weren't so horny all the time maybe we would, but we are so we can't.
Moreover, women are the founding fathers — errr mothers — of the "tease" and isn't a man flirting — yet unavailable — just being a tease?