a variation of the standard
houdini sex act. Perform sex in a doggy-style position, and instead of faking ejaculating on the lady's back as you would in a houdini, you actually do ejaculate. When she turns around, you give her a right hook to the jaw.
Not very nice, but neither is a houdini.
Top points were given to the man who could pull off the most double houdinis and get away with it.