A young friend Peng, visiting the US from China, told me about getting hit on by a man who was "男不男， 女不女" (not like a man, but also not like a woman).
We started talking about gay clubs, and I mentioned that sometimes gay men open with the line, "Top or bottom?" It's efficient, to ensure there's a match before they waste time.
Peng told me what he would do the next time a gay man tried to pick him up.
Gay man: [attempting a come-on] Hey there. [looking him up and down]
Peng: Are you top or bottom?
Gay man: [excitedly waving hand] I'm top!! [pointing at Peng] You must be bottom, right?
Peng: [stepping back] Sorry, I'm not gay.