It's what a clucka (fiend) (dope feind) from Chicago asks a drug dealer when he's looking for his fix (drugs)
Aye you good dog?. . . .what up man you good?
A nonchalant way of asking "Are you high?"or also; "Are you TOO high?"
Jerry: *Wanders in, drooping eyelids, eyes darting around*
Tom: "You good?"
Jerry: "I'm great, man." *Grins*
Sarah: *In class, staring at the ceiling, mumbling to herself*
Jessica: "Sarah, you good?"