[djmcmath]

I was told that "tank slapper" actually comes from motorcycles. If you pull the front wheel off the ground, then set it back down slightly off-center, the various forces cause a rapidly cycling side-to-side motion in the handlebars. After only a few seconds, the amplitude of the cycle will reach the point where the bars are beating into the gas tank, or "tank slapping." It should only take another second or so beyond a true tank-slapper before the biker dies in a fiery explosion.

But I've been wrong before.

Dan