A man and his secretary are having an affair, so one afternoon they get a motel room and have strenuous sex. He's not used to the pace, so he falls asleep afterwards and doesn't wake up until about 8:30 that night, at which time he realizes it's late and that he has to get home.
He says to his secretary, "Quick! While I get dressed, you take my shoes outside and drag them around through the grass and mud." Puzzled, the secretary complies.
When the man gets home about 9:30 his wife confronts him and asks him where he's been. The man says, "I cannot lie to you. I spent the better part of the day doing my secretary in a motel room, then I fell asleep, woke up later, and came right home."
The woman looks down at his shoes and says, "You lying bastard, you've been out playing golf again!"