You could either say "figgis-fiddis" or "F-G-S-F-D-S", but however you say it, it is the one word that makes no sense whatsoever at all. It all started when someone on 4chan replied to a post with "fgsfds". Oryan (a 4chan user) soon shopped the phrase into a pic of some old dude (talk show host, probably) and now everyone on /b/ posts it. When somebody confuses you by saying something that makes no sense, simply say "fgsfds".

fgsfds is a random string produced by typing random letters with your left hand on a standard QWERTY keyboard. The reason people use there left hand is they (usually) have a mouse in the right hand.

For God's Sake, Fuck Dat Shit

A random character string which, through its slyness and intelligence, somehow managed to get past Urban Dictionary's screeners and now has several definitions.

For God Sakes, Fuck Dis Shit

A general keyboard spasm reply similar to typing "asfd" on the keyboard as a filler entry when information is requested. Note: ease of entry on keyboard.

"fuh God's sake, fuck dat shit!"