Pellets tumbling straight at my melon, apparent reason...
Because my cousin's cuzzin a Blood
That was Blooding in public and Kendrick seen with him last weekend, cousin

from Kendrick Lamar – BET BackRoom Freestyle Lyrics on Rap Genius


Since Kendrick was seen with his cousin’s cousin who is a blood, crips shot pellets (bullets) at his melon (head).

Cuzzin is slang for a crip and can be used as a verb here.
The bloods retaliate by attacking Kendrick because of his cousins actions.

Guilty by association, story of my life

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