When dancing at the club: This is when a woman faces away from you, bends over, and uses you like a
stripper pole. This usually includes booty to package contact, with rhythmic grinding, followed with a quick squat performed by the woman to where dat ass either hits the dance floor, or your shoe.
When having
sexuals: This is when, while in the doggy style position or one of its variants, the woman either pushes back upon the
male member and then grinds on the cock while it is fully inside of her, or when the woman gyrates her hips vertically while stroking back and forth on the cock.
lil Wayne in the song, 'Every Girl': "...I just wanna
get behind it, and watch you
back it up and dump it..."
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Bob: What did you do this weekend?
John: Well, Friday, yo mama called me when you went to sleep, and I came over and let her back it up and dump it.
Bob: Shut up!
John: Move out of
yo mama's basement!