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1. The little bit of poop in your underpants that leaks out when you are driving and don't have time to pull over to the bathroom. Your underwear will soak up any moisture and give it the consistency of a fudge brownie. It may also be the result of a shart while driving.

2. Having a passenger give you a rim-job while driving.
A-"Yo Duane did Mary give you some road head on your trip?"
B-"Nah dude, I had some road brownie and almost made her barf in my lap."
A-"I hate it when that happens."

A-"Hey baby it's gonna be a long drive, how about some road brownie?"
B-"Sure, just as long as you don't shart while I'm down there."
by Croganizer February 22, 2014
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