Not My Bag 

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.

Not My Bag by audiomasochist October 28, 2013

that’s not my bag

An informal, often British way of saying “that’s not really my thing”. Thought to be derived from the cult movie series “Austin Powers”

Officer: One Swedish penis enlarging pump for a mr Austin Powers
Austin: that’s not my bag baby

that’s not my bag by TheConmanCometh June 6, 2018

NOT IN MY BAG 

This phrase is used to describe the state of a ambitious individual who hasn't reached his full potential yet, though already being outstanding. Implying there's a lot more to his potential.

"Tyler, you're the MVP of the season, what's more to come?"
"Man, i'm feeling grateful for what's been done but i got a lot more to my potential, i'm not in my bag yet."

NOT IN MY BAG by BROWN PAPER BAG WRLD October 18, 2023