My chain hits my chest
When I'm banging on the radio

from M.I.A. – Bad Girls Lyrics on Rap Genius

MIA got tons of cash for Paper Planes being played everywhere and its
massive success means she can afford a chain.

Also, Paper Planes‘ mainstream popularity would allow for MIA to constantly hear herself “banging on the radio”…
So theoretically she could hear her track bangin’(played loud) in which she is making literal bang, bang, bang noises while she is banging , in the sexual connotation, on her physical radio/dashboard.

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