The effects of feeling slow, hazy and tired after smoking weed the night before. Tends to happen the day after smoking weed before going to bed.
"Hey bro, how was your lecture?"
"I don't know bro, I felt so tired and couldn't concentrate after smoking last night"
"Damn you must have Porridge Brain"
The act of hooking up with a chick and becoming intimate with her private lady parts. An obviously naughty reference to Goldilocks and the three bears where it was presumed that Papa Bear had the hottest bowl of porridge in the household. A calm, respectable reference to hooking up with a chick without saying any dirty words.
Steve: Wow! That chickin the blue is into you.
Chris: I know. She's buying some shots of Jagermeister. After that we're goanna go back to her place and I'm going to get some porridge.