Guy goes to stay over with his girlfriend for the first time, but they have to be really quiet, as her parents are in the house. In the middle of the night he wakes her up and tells her that he really need to use the toilet. She says, "You'll have to use the basin in the corner of the room, otherwise you'll wake my father". After a bit of persuading, he agrees, but then seems to be taking ages. She quietly calls over to him to ask if he's okay, and he replies: "What should I use for paper??".
As a student, I live alone in my small apartment. I piss all the time in the sink but after some months, the bottom of the sink becomes brown-yellowish. I reckon it is because piss is slightly acidy and it started rotting the sink. Hope it helps!
Ho ho!