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 16, 2006
Get the the brainermug. The satisfaction you get when learning something you didn't know before or to share something else with someone who didn't know about it before. Like a boner, but with your brain.
Mary: John must be the most common name in the world.
John: No, Muhammad is the most common name ever.
Mary: Oh. I didn't know that.
Tommy: Total brainer.
John: No, Muhammad is the most common name ever.
Mary: Oh. I didn't know that.
Tommy: Total brainer.
by Three years later July 17, 2010
Get the brainermug. 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
Get the Brainermug. 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
Get the Brainermug. 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 1, 2021
Get the Brainermug. 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 January 3, 2016
Get the Brainermug. When you're attracted to somebody primarily based on their personality and mind rather than appearance (although that does help).
"That thing you just said was so cute. I have an erection for you, but in my mind. I have a brainer."
by bobplate May 5, 2014
Get the Brainermug.