An old retired sailor puts on his old uniform and goes down to the docks once more for old times sake. He finds a little prostitute and goes up into the room with her, draping his sailor suit across the bed.
He's goin' at it as best he can for a guy his age and asks, "How am I doin'?"
The whore says, "Well, sailor, you're doing about three knots."
What's that?" he asks.
She says, "You're 'knot' hard, you're 'knot' in, and you're 'knot' getting your money back!"