Gender fuck - the art of appearing to be a gender other than that which society has traditionally placed on the gender fucker.
Often used as a means of political expression, eg. of the celebrating diversity sort.
Probably includes drag kings but not drag queens, as the latter is somewhat more accepted than the former, and because androgyny seems to be more achieveable by the 'fairer sex' than the other.
I have gender fucked you when you don't know whether I'm a man or a woman, or if you decide on one but discover I'm the other (through genital observation).
An amusing game to play in single-sex environments, if you like to live dangerously.
More exciting to play in RL, due to the confounding properties of voice, expression, body language and physical appearance.