to be reamed unknowingly, usualy from behind while still wearing ones underwear. resulting in undies being stuffed into the oriface in question
i gave that bitch from starbucks a rightious undie punch..
she was all like

"AWWWWWW i say stop that young man dont punch my underwear into my date"

"captain to the bridge, there has been a royal undie punching on the lower deck"
by reg the great October 2, 2007
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To punch someone in the undies. With your penis usually.
Me: How was your date last simo? Any undie punching?
Simo: Hell yeah, was awesome too. Plenty of undie punching to be had.
by Rodney Stewart March 13, 2008
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