Is a rare and abandoned acronym for the phrase,
"Get the fuck off my face, mother-fucker"
It was abandoned for the simple reason that

"g-t-f-o muf-muf" is quite an unwieldy and difficult to use combination of sounds.
Person 1 "Don't go in there, Its filled with head-crabs"
Person 2 "It's fine I have a wrench, wait no . . . OMG gtfomfmf"
by Kingtelmar January 21, 2012
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