A combination (or portmanteau) of the words "moist", "ass", and "barf" all in one. It pretty much means poop or diarrhea, but with a funnier sounding word.
Person 1) "I totally just marfed on your birthday cake!"
Person 2) "That's okay. Maybe we can eat your marf and vomit all over each other!"
Person 1) "Only if you fist me!"
Person 2) "Deal!"
Person 2) "That's okay. Maybe we can eat your marf and vomit all over each other!"
Person 1) "Only if you fist me!"
Person 2) "Deal!"
by Green Bean Boy December 3, 2010
Get the Marfmug. by MREASTMASTER69 December 11, 2009
Get the Marfmug. That motherfucker marfed your prospect.
by Dr. Jrock October 22, 2010
Get the marfedmug. by DJ KRUNCH! October 27, 2007
Get the Marfmug. That humurous fart when it starts out with a pop, immediatley followed by a long high pitched sound ending the fart. Sounds like, "Pow, weeeeeeee"
by Jimbo75 October 3, 2011
Get the Marf Weaselmug. 
by FUCK PETE April 12, 2022
Get the FUCK MARFmug.