Top definition
The act of jumping or running and subsequently having your scrotum smack against your thighs and causing a clapping noise to be made.
Last night at the party, i was fist-pumping in front of Katie like a total douche, because women totally like douche's, and i thackwhapped right in front of her, and she started laughing.
by RoflCOCK April 21, 2011
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