Abbreviation for "Oh my fucks!". Particularly used to replace "Oh my gosh" from "oh my god" when trying not to use the word "god", or having "gosh" mistaken for it. Can be used by either fundies or atheists, either not using "god" because it's a sin to use it in vain, or merely because you don't believe in theism and don't want to support it.
omfux u fartid !
omfux i just got pooped on!