A Brainer is when you do something because it had to be done and you knew it was the right thing to do.
by WolfBrother13le April 24, 2013
It's when you grab the skin between your hanging balls and your cock and then tighten your grip all the way up to your balls forcing them to really stick out, this makes your sac look veiny and bumpy like the top of a brain.
I asked my girl to examine a spot in my testes, when she came in for a closer look, I tightened up my grip and hit her in the eye with the brainer.
by allen powell January 17, 2006
brainer or brain boner is when something satisfies the mind in a way to the extent of giving a mental erection.
Jimmy: "hey Dave did you know that 69,000 + 420 = 69,420"
Dave: "Jimmy you just gave me a raging brainer with that one"
Dave: "Jimmy you just gave me a raging brainer with that one"
by Beekmaster21 November 24, 2019
person 1: I pulled my wee wee out and she did not want to suck it
person 2: yeah she is known as the only girl who doesn't give head she's a no brainer!
person 2: yeah she is known as the only girl who doesn't give head she's a no brainer!
by DefTheDefguy July 25, 2022
A word used by senior stagiaires who are trying to look cool. While the validity of the word is contested, it is accepted that the word is not used by anyone anymore, or at least anyone who you would consider to be cool.
Christine: This guy I know went did a degree in engineering and a masters in engineering and now he is in med school doing his residency, what a brainer!
Mat: What's a brainer?
Mat: What's a brainer?
by trusted authority November 18, 2011
To produce a brainer, wrap your hand around your ballsac and squeeze, your nutsac will bulge out between your thumb and forefinger simulating the look of a brain
by De ranged July 01, 2021
The act of exhaling Marijuana from one persons mouth to another persons mouth, to be then inhaled.
See also: Shotgun.
See also: Shotgun.
by kamoke November 02, 2015