A fork of Rural Dictionary
To not be of someone's 'thing,' interest, taste or expertise. A polite way of saying that you have no interest whatsoever in what is being suggested or discussed. Can also be used in admitting ignorance of a certain subject. Compare 'bag' to cup of tea. Perhaps derived from 'bag of tea.'
1. Guy: Want to come to the body building show with me this Sunday? Gal: Uh, no, that's not my bag. 2. Fellow: Do you know any jazz clubs around here? Buddy: Sorry, that's not really my bag.