1. Shear extreme surprise.
2. The flapping of a holy ones ass cheeks, such as the pope.
3. When something so crazy happens that Jesus applauds you with his ass cheeks.
-A ass ninja
flys out of nowhere briefly and then disappears into the shadows.-
Justin: Holy flapping ass cheeks! Did you see that ass ninja!
Matt: ....... -Slaps Justin for shear stupidity and then quickly disappears just like the ass ninja-
Justin: -After realizing that Matt was the ass ninja- Holy flapping ass cheeks!