Zefram: I gotta take a leak.
La Forge: Leak? I'm not detecting any leak.
Zefram: Don't you people from the 24th century ever pee?
Zefram tells La Forge he needs to pee by telling him he needs to take a leak. La Forge is all concerned about a potential leak. Zefram responds with asking if people of the 24 century ever pee.