While I was presenting my project, the student across from me thinks he can start feather flexing by cutting me off and asking all these questions.
by JG.F.AV November 3, 2019

The act of “putting your money where your mouth is” by rising to the occasion or backing down. Much like “nut up or shut up”, it is a challenge to someone who has said that they would do something to show strength—usually an aggressive or bold course of action. It is frequently an ultimatum to call someone’s bluff after they’ve been running off at the mouth about what they could or would do in any given situation. The term is used to shut down foolish declarations made by wanna-be types who have something to prove to themselves and others, but they often lack the ability to follow through.
Girl #1: “If Karly tries to step to me, she can catch these hands!”
Girl #2: “I think Karly might have heard what you said…she’s coming over here.”
Girl #1: “I don’t care if she heard!”
Karly: “Oh, yeah?!? Flex or fold!”
Girl #1: “JK, Karly…you know you’re my girl.”
(After mean-mugging Girl #1)
Karly: “That’s what I thought.”
Girl #2: “I think Karly might have heard what you said…she’s coming over here.”
Girl #1: “I don’t care if she heard!”
Karly: “Oh, yeah?!? Flex or fold!”
Girl #1: “JK, Karly…you know you’re my girl.”
(After mean-mugging Girl #1)
Karly: “That’s what I thought.”
by Gemini Grammarian February 4, 2022

When somebody flexes on the fact that he/she is in a relationship. This type of behaviour usually includes having interactions with a partner that is supposed to be private for example kissing. Instagram pictures where the couple is making out can also be considered this. This type of behaviour is usually quite despised and cringed at since it makes everyone feel uncomfortable, no matter the observer’s status (single or not).
Have you seen Jake’s new insta photo with his girlfriend. It’s so obvious it’s just a relationship flex. Jeez, it was so cringe.
by rudi.k July 23, 2019

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

When a women is in a split position, or a squat or on there knees, flexes or contracts her booty muscle. This is a type of twerk also known as booty control.
by dj hamid November 9, 2014
