1 definition by katiegurl19512

n. the cleavage at the bottom of ur butt and top of ur leg. Usually on girls with bigger butts. Also known as under tuck.
Guy 1: Damn! do u see that chick over there? shes got a nice ass!
Guy 2: Yeah shes got a nice under butt too!
by katiegurl19512 October 23, 2009
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