What a surprise!

A man walks into a bar, late one night completely knackered and dripping with sweat and orders 5 whiskies.
"What's wrong with you?" The barman says.
"In my car I've got a nymphomaniac - you couldn't satisfy her if you were there 'til Christmas," he replies.
"We'll see about that," says the barman and goes out to the car park.
He has been in the car with the woman for a while when there is a knock on the window and a policeman shines his torch in. The barman jumps up and winds down the window to talk to the policeman.
"It's all right officer, I'm just shagging the wife," he says.
"Oh, I'm sorry sir, I didn't know it was your wife" replies the cop.
The barman replies -"Neither did I 'til you shone your torch!"