Lady Of The Night
A man's walking home late at night when he sees a woman in the shadows. "Ten quid for a quickie," she says.
He'd never been with a woman like this before, but he decides what the heck it's only ten quid. They're getting friendly for a minute when all of a sudden a light flashes on them. It's a police officer. "What's going on here, people?" asks the officer.
"I'm making love to my wife," the man answers indignantly. "Oh, I'm sorry," says the cop, "I didn't know."
"Well," said the man, "neither did I until you shined that light in her face."