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1.
Prostituting oneself for the sake of it being an easy way to get cash, when you sleep around for money but dont actually have to
"Why work at Taco Bell when i can make 200$ a night flat backing?"
by Oidua November 20, 2006
 
2.
A bitch or bird with no job who sleeps around for money and material things.
Yo! How did Shawty get that Gucci Bag, she don't work even no where?

Ans: Shawty be flatbacking.
by V Double November 08, 2010