keep on about
keep (going) on about (someone or something)
To continue or speak for a tedious or exasperating length of time. My date kept going on and on about his charity work, never even asking what I do for a living.
keep (going) on about (something)
To speak about something tediously and at great length. Primarily heard in UK. He just kept going on about literary metaphors and imagery. I didn't know what he was talking about! She always keeps on about some new show she has started watching.
keep (going) on about someone or something
to continue to talk excessively about someone or something. I wish you would not keep going on about Tom and Jill. Don't keep on about my haircut. It's perfect!