the act of un-tucking, or keeping a boner un-tucked from the waistband while dancing, thus, causing it to annoyingly protrude onto the date's butt

*this can only occur with a penis larger than about 2 inches*
Did you see that kid?! He was rockin the slip n grind alll over kristen's ass! What a noob.
by Nidam Perick October 28, 2007
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