From Longman Dictionary of Contemporary Englishbang on phrasal verb British EnglishTALK TO somebody informal to talk continuously about something in a boring way SYN go on about I wish he wouldn’t keep banging on about politics. → bang→ See Verb table
Examples from the Corpus
bang about• The North will not get that investment if certain influential people keeping banging on about how wonderful things are.• I won't go banging on about the open fireplace again, but to my mind that was certainly one of them.bang onbang onBritish English spokenCORRECT exactly correct ‘Is that right?’ ‘Bang on!’ → bang 