Don't snort the white horse, but toot my own horn
Since he’s a Muslim who follows his faith devoutly, Lupe doesn’t do drugs (“horse” is slang for powdered heroin), but he does toot his own horn (promoting himself and his records). A unicorn is a white horse with a horn. Horses often “snort” when they neigh.
Note that the reference to tooting his own horn foreshadows the tuba reference in the next verse.
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