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.