I didn't happen on the flop, but I'll win it on the river
The reference is to Texas hold'em poker — “flop” and “river” designate, respectively, the first three community cards dealt, and the last community card dealt. As for the double meaning, the “flop” was his album The Old Prince and “the river” could be his album TSOL (on which this track appears). The former didn’t achieve much commercial success, but Shad claims he succeed with his latest effort.
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