Having diarrhea; specifically, the act of expelling diarrhea
"I shouldn't go to the amusement park today. I've been fartbarfing all night after I ate diarrheadonalds."

"Oh no! Why did this happen today?! I can't be fartbarfing during my wedding ceremony!!"
by Jessman January 23, 2014
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It is when you fart out barf from when someone threw up inside your anal cavity while really tossing your salad deeply.
Linda threw up while tossing my salad, which caused me to fartbarf all over her face.
by Sinbadass December 11, 2011
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