" A red rag to a bull "
Meaning:
A deliberate provocation.
Example:
Telling Putin that he is macho as a response to being small in stature was like a red rag to a bull.
Where did it originate?:
The United Kingdom. An allusion to bullfighting, where the bull is provoked by a waved cloth.
Where is it used?:
Hear the idiom spoken: