keep on about
Intermediate (B1) informal
To keep talking about the same thing again and again until it annoys people.
"My dad keeps on about how cheap petrol used to be when he was young."
Hear it in context
Invasion of the ROBOTS | Doctor Who Night
Doctor Who · 39:00
You're not going to keep on about it.
The Doctor Faces An Impossible Astronaut 😱 | 15 Years of Series 6 | Doctor Who Night
Doctor Who · 41:07
You're not going to keep on about it.