When a male twists his mid-dection left to right in such a way that his penis slaps against each thigh repetitively.
When you get out of the shower, sometimes while drying your back with your towel one end in each hand the Thigh Thumper may occur.

Another instance is when getting naked for sex and you show off to your gf saying... want to see what I can do?
by Dr. Keif February 16, 2011
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