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1.
no bra no panties. You can mean 2 things by this saying.

1. You're not a virgin (or not a virgin anymore).

Or

2. You're sexually putting yourself/ sexually marketing yourself out there.
Taken from the movie "Thirteen". The scene with Traci and her Mother. no bra no panties:

Traci: *Dancing and touching herself* No bra! No Panties!
Mom: *Fearing the worst* Stop it..
Traci: No bra! No panties...
Mom: 0_0
by Erik/Raoul March 20, 2010