bat brain 

a move personally made up from the batwing, a cruel joke, mostly done by other teenagers, where you take your scrotum, spread half of your sac out with your hand, and cup the other nut in your hand like a brain. takes a while to get right, but when accomplished, is better than the batwing

I flashed robert with the bat brain, and he threw up!

Adam scared a kid with the bat brain.

bat brain by bodhi williams March 30, 2008

Bat brain 

When a person/persons hangs from the ceiling by their feet which then a male proceeds to put his penis in their mouth and continuously aggressively fucks her throat until he cums down her sore airways.

“Hey Nathan, I wanted to give my girlfriend bat brain last night but she was too heavy and she snapped the rope”

Bat brain by @kinggy May 9, 2020

Batbrain 

A Batman fan who always has Batman on the brain.

Ever since Tim saw his first Batman movie, he's been a total batbrain.
___________________________________________________
Mr.Person A:Yesterday I saw some nerd running around in a Batman suit.
Mr.Person B:What a batbrain.

Batbrain by Wilddwarf June 27, 2009