That’s how I imagined it must have sounded when my student said there was a noise in his head right after I flicked the back of my palm against the side of his head. The weird part was I had tapped the right side of his head but the noise was heard in his left ear!
I didn’t know what to make of it except to assume in hindsight that the tap must have rung his head like a bell and projected the sound to the other side. To me the more interesting reaction was how the tap caused him to stop immediately. Though, I did not intend to actually made contact, that it did inadvertently yielded this observation.
So if you ever wonder if a flick of the wrist is effective this anecdote suggests that it is. Of course, the other question would be how would it be if the target struck had been the face head-on. Silly question. A tap to the face can stun and with a bit more force can break the nose.
Fun fact to know. Just be careful when practicing this way.