Made up word? Yep. Has no offence? Nope, not even close on this one.
As our language arts-teaching colleagues reminded us one day at lunch (when we were discussing this very word, and whether a young man who used it in a classroom in a way that left no doubt what his intentions were... lots of words have been created to fit an occasion, and are now generally accepted parts of our language. Doesn't matter how they come to be - what matters is how they come to be used.
Bottom line - an F-bomb is still and F-bomb, no matter whether you change a letter or three. It's the intent behind it.
Want a nonsense word that doesn't cause problems? Pumperquarter is a good one to try!