To send a vital message out to all of y'all homo sapiens
Waterfalls, don't go chasin' 'em
Stick to your rivers and lakes
And don't swim in the first place

from The Palmer Squares – MC Showcase 2011 Lyrics on Rap Genius

Meaning

A pun on “homo sapiens” and an actual insult to his enemies (homos).

Also an allusion to the song and saying popularized by TLC, “Don’t Go Chasing Waterfalls”, meaning be happy with what you have. Don’t chase something you think you need because it could potentially be bad for you.

Ac is warning other rappers, specifically shitty weak ones, to stay in their league (rivers and lakes) or better yet to not even rap at all (don’t swim in the first place).

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