My pockets filled with them stacks, my bitch be gone off a flat
from Chief Keef (Ft. 50 Cent & Wiz Khalifa) – Hate Bein' Sober Lyrics 1 on Rap Genius
Meaning
His pockets is filled with stacks of money
And his bitch is high off a pill
Flats are a type of pill like Xanax pills which are flatly shaped.

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