A: John is always flexing on social media — showing these glamorous pictures of his holidays!

B: Those must be photos he took a while ago. Isn’t he staying at home like everybody else now?

A: Indeed. He’s always trying to show off.

Note: Literally “to flex” means “to bend.” The idiom “to flex one’s muscles” literally means “to contract one’s muscles, especially to demonstrate their size and strength,” and is often used as a metaphor for “demonstrating one’s influence, power or strength.” The slangy use of “flexing” derives from that idiom and means “showing off” or “pretending.”