an old retired sailor puts on his old uniform and goes down to the docks once more for old times sake. he hires a prostitute and takes her up to a room, he's going at it as best he can for a guy his age. the old sailor asks, "how am i doing?" the prostitute replies, "well sailor, your doing about three knots." "three knots?" he replies, "whats that supposed to mean?" she says, "your knot hard, your knot in, and your knot getting your money back"