Mud Brain 

after the act of sodomy, you receive fellatio

that chick Rachael was a freak, she gave me mud brain, and i accepted in a drunken stupor

Mud Brain by Lord-Gore May 26, 2010

Mud Brain 

Occurs during to the seemingly FOREVER period of time between running out of ADD meds and becoming eligible to refill. In most cases, said person becomes unable to function in any sort of productive or sensible way. Withdrawal symptoms include but aren’t limited to; complete loss of ability to focus,

Nan: Oh my god, dude. I have total mud brain! Can't refill for 6 days!
Bert: I know, right?
Nan: I’m gonna go outside and drag my face on the concrete
Bert: Chewbacca does not live on Endor

Mud Brain by ChellChell September 9, 2010

Mudbrain 

A stupid person.

Maddison, you don't even know how to read, you're such a mudbrain

Mudbrain by The fact that September 23, 2015