A variant of the 69 position involving a horizontal beam. Person A hangs upside down while person B stands on an item of appropriate height to facilitate a junk in face orientation for both parties. Although originally developed in a log cabin, this position may be applied creatively to a variety of locations including sailboats and monkey bars. Other names include the beam ream, the leaky ceiling, the km special, the log snog, and the boom bang (nautical).
We were caught doing a rafter shafter and tried to explain we were fixing a leaky ceiling.