1
general::
Phrase(s): What’s coming off? [and] What’s going down?
Sl. What is happening here?; What is going to happen? (Also a greeting inquiry.) • Bill: Hey, man! What’s coming off ? Tom: Oh, nothing, just takin’ it easy. • Bob: Hey, we just got here! What’s going down? Bill: What does it look like? This is a party, dude!
McGrawhill's American Idioms And Phrasal Verbs