Viz Magazine UK
first used the word on the cover of the magazine to annoy Newagents(WHSmith)by creating an imaginary very rude swearword.
This was first used by Viz Character 'Sweary Mary', and is allegedly the rudest swearword in the world.
Can be used as an alternative to c*nt or f*ck as in the example.
"Oh fitbin, I've just stepped on a dog turd" or as Derek & Clive may have said "Adolf Hitler, what a fitbin he was....."