It's basically a way to say hi or whats up to another individual
say=hey brah=bro
say brah = hey bro

The horrible moment when you realise that you have accidentally done something very slightly wrong which has very bad (usually embarassing) implications for you. This is typically the moment of realisation that you just sent a dirty text message to a close member of family, typically your mother, rather than the intended recipient.

Slang for: what's going on bro
or like
what's good
used mainly by frat guys or badass girls