A girl takes her new boyfriend back home after the school disco. She tells him to be very, very quiet as her parents are asleep upstairs and if they wake up, she’ll be in big trouble as she’s not allowed to bring boys home.
They settle down to business on the sofa, but after a while, he stops and asks “Where’s the toilet? I need to go.”
She says “It’s upstairs, next to my parents bedroom. But you can’t go up there, because you’ll probably wake them up. Use the sink in the kitchen instead.”
He goes into the kitchen and after a short while he pops in his head round the living room door and asks “Have you got any paper?”