Rabbit on
Definition 1 of 1
Pro Tip 1/3Cultural Nuance
Primarily British usage; may not be understood in other English-speaking countries without explanation. 
When I studied in the US, people seemed confused when I mentioned how my friend rabbits on.
Pro Tip 2/3Casual Contexts
Use 'rabbit on' in informal situations, like chatting with friends, not in formal speech or writing. 
During our coffee meet-ups, Sarah tends to rabbit on about her hobbies.
Pro Tip 3/3Negative Connotation
Implies annoyance; it's not a compliment to say someone rabbits on. 
The meeting dragged because the manager rabbit on about outdated policies.