A man is invited to join his fellow workers for a drink down the
pub after work. "Sorry mate" he replies, "the wife wouldn't like it".

"Sod the Wife" says his colleague, "what you do is come out for
a drink with us, then when you get home you go into the bedroom,
slide under the covers and go down on her, she'll be enjoying
herself so much she won't mind what time you came in."

Four hours and several pints later, the guy wanders off home.
When he gets in all the lights are out so everyone is in bed. He
creeps upstairs, climbs under the bed covers and goes down on
his wife. She is groaning and rolling around in pleasure. After a while he decides he needs a pee so creeps down the hall to the bathroom. When he gets there he sees his wife sitting on the throne.

"Bloody Hell, that was quick" he shouts.

"Sssshhhhh" says his wife "you'll wake my mother!".