1. When you are stuck in traffic and you take a shit in a cup and stash it under your seat.

2. A ho you bring on a long road trip.
"Damn i left a road muffin in my car and now it smells like shit!"

"Jenny's my road muffin, she gave me head all the way to Denver."
by Gorman 1st floor May 17, 2008
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Man, I'm glad she wore a skirt so I could give her a little road muffin on that long drive.
by branda8888 January 5, 2010
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