to engage in a physical encounter
"Oh, you talkin' that slick shit? Huh? You wanna bang? Huh?"
- Tim and Tom Win
To beat up/physically assault. Mainly used in South London
"Shit bruv, I got banged in the face by those boys."
"Shut your mouth before I bang you up."
Gang relations
If somebody is banging then they are possibly representing a gang
to squad up or to get ready to fight
like whats good nigga what wonna do u wonna bang or what nigga