The Brief: To stop someone's bag means to prevent someone from making money.

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Stop bags is a slang term referring to getting in the way of someone’s source of income, usually by outcompeting them. It can also be used more generally to mean getting in someone’s way or sabotaging them.

The phrase was incorporated into a popular hashtag,#NickiStoppedMyBag, that references Nicki Minaj allegedly stopping Cardi B‘s bags.