"YAWK! YAWK! YAWK! YAWK!"

from Kendrick Lamar (Ft. MC Eiht) – M.A.A.d City Lyrics on Rap Genius

Q’s signature, he tends to scream it in many of his songs, like “Unnecessary” by Childish Gambino. It’s also a gang reference to Q’s days as a Hoover Crip. This is his imitation of the loud blast of a gunshot. Kendrick uses this ad-lib to describe the multitude of gun violence that occurs in his neighborhood. .

In practice, something like this:
https://vine.co/v/bLbmvjnhBuj

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