Originally used to refer to a cheater in the gentleman's sport of golf from the disingenuous act of picking up one's ball from the green in order to wash it then subtly replacing it closer to the cup. While meant as an extreme insult when people cared about such things, it has maintained its weight by now being used with obscene implications.
That ball-washing bastard!
giving someone excessive flattery. Recently popularized by the Petros and Money show on Fox Sports Radio.
John Madden has been ball-washing Brett Favre for years.