A big girl’s blouse
Definition 1 of 1
Pro Tip 1/3Colloquial Usage
The phrase is informal and might be considered rude or insensitive in professional contexts or with strangers. 
He called his friend a big girl's blouse for not watching the horror movie.
Pro Tip 2/3UK Specific
Primarily found in British English, might not be understood or used in other English-speaking countries. 
When I said 'big girl's blouse' in America, they didn't understand what I meant.
Pro Tip 3/3Gender Connotations
The phrase can reflect gender stereotypes that may offend, so use it carefully and know your audience. 
Calling someone a big girl's blouse might seem funny among friends but could offend others.