to continue;
to talk for a long time

Example Sentences:

Sorry, I didn’t mean to interrupt you. Go on with what you were saying.

A: …and that’s why Canada is the best country in -
B: I disagree! America is better!
A: Excuse me, don’t interrupt!
B: I’m sorry, go on.

Scott is always going on about the Zeitgeist movie.

Media and Links:

Similar idioms:

1. fresh off the boat
2. excuse my French