A man was walking late at night when he sees a woman in the shadows.
"Twenty bucks," she says.
He's never been with a hooker before, so he decides what the hell. They're going at it 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," he answers indignantly.
"Oh, I'm sorry, I didn't know," says the cop.
"Well, neither did I until you shined that damn light in her face."