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 started when an anonymous replied to a post with "fgsfds". A namefag, Oryan, then shopped the phrase into a pic of German talk-show presenter Harald Schmidt.
When somebody confuses you by saying something that makes no sense, simply say "fgsfds".
fgsfds is commonly photoshopped onto pictures of anyone pointing their index finger in the air.