Water Pick

When someone has a piece of food stuck in their teeth and no dental floss or anything else to get it out, so you offer piss in their mouth to dislodge it, similar to a real dental water pick.

Mike: I've had this chunk of meat stuck in my teeth and can't get it out. This is insanely annoying.
James: If you want, we can step into the mens room and I can give you a water pick.