black brain 

The loss of brain cells due to the excessive use of marijuana, resulting in getting stuck on a word or thought

Dude that girl was rambling on, def black brain

black brain by Janet flight August 31, 2017

blank brain 

When you are so stoned and don’t wish to feel emotions so you just zone out.

Yo dawg is she good she looks like she went blank brain

blank brain by Blakley January 6, 2021

Back Alley Brain Transplant 

The act of being dragged into a back alley and having your face punched in..... and your brains punched out, figuratively speaking.

Tom: Hey, have you heard all of those kids obsessing about Twilight?

Steve: Yeah, I want to give each and every one of those kids a back alley brain transplant

Back Alley Brain Transplant by I'm_Not_Violent April 4, 2009

Brain block 

When one is lucid dreaming and your brain steps in and blocks it.

I was flying around and my brain blocked, so I woke up.

Brain block by Pavlovsdog May 29, 2021

Put that back in’t brain 

A Yorkshire expression used when someone has said something stupid that they should not have said.

Clive: “y’know, I prefer Tetley’s to Yorkshire tea”
Derek: “Clive, you idiot, put that back in’t brain!”

Put that back in’t brain by FistyWayne July 8, 2021

Blackrainbow 

Electro sexual music compositions that leave one with psychedelic but danceable emotions.

1. The uncontrollable discolorations of vision resulted from the beat.

2.Gspider and Maya Fords musical interactions create a Blackrainbow.

3.Should I dance or gaze in bliss.

Blackrainbow by Zennon5 May 12, 2009

backbrain 

The repository of knowledge one retains but doesn't realize one has until such knowledge is necessary in a given situation (e.g. recalling the name/face of an old acquaintance/friend/girlfriend)

"I was walking to work and some guy asked me where I went to school; I thought he was a creep until my backbrain kicked in and I realized we lived on the same floor freshman year."

"I couldn't figure out why she slapped me until my backbrain kicked in and I remembered that I slept with her best friend a few years back."

backbrain by F_Oxford June 19, 2014