1. Laughing and/or chuckling (like a crazy person)
2. Fooling (Like joshing, joking, etc.)
From Gangster's Paradise by Coolio: "Cuz I been brassin' and laughing so long, that even my momma thinks that my mind is gone"
1. Ian has been brassin' and laughin' so long that even Bennie thinks that his mind is gone.
2. Ian said he wouldn't tryout for football, and Bennie was mad, until Ian informed Bennie that he was only brassin' him.