1: A tax men pay in order to get laid. 2: Having to do something with your girlfriend that you ordinarily would not do. The thought being that you're only doing it in order to get laid (eg: attend a chick flick, a play, or an art gallery).
dude #1: Have you seen that horrible Tori Spelling show?
dude #2: No.
dude #1: I was at my girlfriends last night paying pussy taxes
and had to watch it. It's horrible.