flying on yourself

Acting overly self-assertive or self-confident.

Julia: "Hey Daniel i'm so good at reading people!"
Daniel: "Jeeeeessss Julia, stop flying on yourself!"

fly on yourself

A popular saying in Hebrew which means being arrogant.
Someone that flatters himself or consider himself better in something that he is not.

Person A: "I'm gonna kick your ass on that game"
Person B: "don't fly on yourself, I am better"