I'mma smoke till I'm bat shit
Guano, which is literally the shit of bats, makes a good fertilizer due to its high levels of phosphorous and nitrogen. Basically, El will smoke til he’s dirt, or dead. Similar phrases are “Doing dirt like earthworms” or “Pushing daisies”.
Or it means that he’ll smoke til he’s crazy, as “batshit” is a colloquial term for it (see also: batshit insane/crazy).
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