bang on
1. verb To strike something repeatedly. Quit banging on the door, I'm coming! How much longer will your little sister bang on the piano tonight? I'm getting a headache from all that racket.
2. adjective Exactly right. I think that is a bang on analysis of Forster's novel. My estimate was bang on. I hope the boss notices!
bang on someone or something
to strike someone or something repeatedly. (Especially to beat on a person or a drum.) Please stop banging on that drum! Max was banging on Lefty when the cops arrived.
bang on
exactly right. British informalbang/spot ˈon
(informal) (of an estimate, a description, etc.) exactly right: She was bang on when she called him an idiot: that’s just what he is!Your sales estimate was spot on. Well done!