on (one's) hobby-horse(redirected from on hobbyhorse)
on (one's) hobby-horse
Frequently or incessantly talking about a subject, topic, or issue in which one is excessively interested. Ah, here we go again. Once Grandpa gets on his hobby-horse about the government, there's no stopping him! Uh oh, sounds like Janet is on her hobby-horse again about the need for healthcare reform.
See also: on