Relating to the fact that Osama or Usama Bin ladin was shot twice in the face by U.S. Special operations forces which inevitably caused his death on May 1st 2011.
Osama Bin Dyin!! I saw his face all bloody on the images of a search engine.
Coined by the webcomic, XKCD, this is a play on the song title "Rock me Amadeus", a popular song from the mid 80's from an Austrian pop musician (Falco).
One could utter this phrase when joyful with respect to Barack Obama's actions, or merely his presence.