What is Boob Crack?
1.
When the bottom of a girl's boob is hanging out from under a woman's top.
Did you see that chick at the club showing her boob-crack
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2.
the cleavage spilling out of a girl's shirt.
Mya Braztoosmal: Um, what are you staring at? My eyes up here kid.
Kid: Oh, I was just staring at your boob crack.
See