Only said with an accompanying "double-guns"...both hands formed into pistol formation and rotated quickly at a target.
Arising out of gang shooting references, it is recognizing someone or singling that person out.
First person: Yo, I gots the perfect idea!
Second person: *double guns* Bam!
First person: Uh, what was that all about?
Second person: It's all good, lay it on me, my brutha.
First person: I forget now...
Second person: Word.