cobra trainer

A "cobra trainer" is a person who always one ups you by saying they also did it or did it better or did it more often.

Tammy: Stephanie is such a cobra trainer!
Tiffany: Why, what did she do now?
Tammy: I told her about my visited China and was giving her the highlights of my trip. She said she's also been to the same places and claimed to have been to many other.
Tiffany: That's possible.
Tammy: She's never even been to China!