When I be flipping 'em
Basically the same as when he said kicking ‘em.
“Eminem describes how once he grabs the Microphone, he "flips ‘em” which is a way of saying how “ill” he is. When someone describes doing something physically harmful (i hit it, i kick it, i destroy it, i slaughter it, i kill it, i flip 'em) on the mic, they are complementing themselves."
Also, in producing, to “flip” is to flip a sample in order to make a good beat. But Eminem probably isn’t talking about producing because this song is about MCing skills, not beat making.
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