Fully dedicating your time and effort into unlocking an acheivement in a game to the point where you haven't showered in days and then sharing for everyone to see in a sort of bragging kind of way
You seen the new gun that just came out in COD? It literally just came out yesterday and my friend unlocked everything for it already. It was all over his social media. Major sweat flex.
by AwesomeAlex808 January 26, 2020

Person 1: Yeah, I have a $4500 PC. It has a 3090 in it.
Person 2: Stop fucking passively flexing, you dickhead.
Person 2: Stop fucking passively flexing, you dickhead.
by Ding dong, the bitch is dead! November 3, 2021

Where a "flexer" uses someone else's flex power and pass it off as their own therefore committing Flex Fraud
Flexer: look at my car collection in my garage
Friend of the flexer: Isn't this Davids? why are you committing flex fraud?
Friend of the flexer: Isn't this Davids? why are you committing flex fraud?
by FadingSins January 18, 2020

Flexing done prepared, not just out of the blue. Originated from Lil Tay's flexing, and the opposite of uncoordinated flex in which people flex at anytime anywhere.
by FL4ym3Burn June 13, 2018

When a man gives himself a prostate orgasm and ejaculation by laying on his stomach and flexing his ass muscles up against his prostate to stimulate it. This can be done when the penis is either erect or flacid, and nothing needs to go inside your rectum. It's like bottoming solo.
Luke doesn't jerk off, he flexes off. Why can't you masturbate like everybody else does, Luke? Why do you have to figure out ways to have better orgasms and keep this shit a secret, Luke? I want to flex off too. Wow I bet Luke is great in bed, he knows all kinds of secret tricks.
by IcyHot June 9, 2017

To show off on social media (mostly Twitter hence the name) but since your on social media people can't tell if your lying. But if it's Twitter flexing then it is most definitely a lie
Guy1: holy shit this guy on twitter got like 100 coupes!
Guy2: boy that's a Google image. He's twitter flexing.
Guy2: boy that's a Google image. He's twitter flexing.
by Mc BushPig June 16, 2017

by Kaichester August 29, 2009
