Ride (one's) hobby-horse verb phrase
“Hobby-horse” or “hobbyhorse” have the same meaning.
To frequently or constantly talk or complain about one's favourite topic or issue
Don't mention K-Pop or she'll ride her hobbyhorse!
Sue starts to ride her hobbyhorse again about vaccines.
Used to describe someone who is good at persuading people to do or believe something
To complain about something in an annoying way
Primally used in the UK to indicate the typical manner of communication from the high social class
Used to imply that one talks for such a long time that someone becomes tired or bored
The verb "ride" should be conjugated according to its tense.
The hobbyhorse is a toy of yesteryear, dating back to a homespun era predating automobiles. In the 1400s, the word hobby could refer to a real-life horse of small or average size. It soon came to refer to the horse costume worn by one participating in a morris dance or burlesque performance, and then, later, to the child's toy. Another meaning of hobbyhorse was "a favorite pursuit or pastime"; our modern noun hobby ("an activity that one does for pleasure when not working") was formed by shortening this word. From "pastime," the meaning of hobbyhorse was extended to "a subject to which one repeatedly returns." The sense is typically encountered as part of such metaphorical phrases as "get on one's hobbyhorse" or "ride one's hobbyhorse."
Used to allude that the last force, problem or burden which is seemingly minor and small causes a person, system or organisation to collapse or fail
Her husband's violent act last night was the straw that broke the donkey's back and she left him