But I done did enough codeine to knock Future into tomorrow
He teases new-school rapper Future, because he always “raps” about how he drinks codeine . Also, a play on words with Future’s name. The future is tomorrow (and also contrasts the past in the previous line). So he’s going to knock Future into tomorrow. He may have tried to avoid the harder stuff in his past, but he went through recreational drugs like lean like they were nothing.
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