I tried to copy what you did and fuck no could I do that longer than a couple of minutes:
A) It made me dizzy spinning and shit and I was like WHATS GOING ON!
B) Made my hand ache
I tried to copy that and it wasn't hard at all, though with my playstyle it doesn't add much. In some situations I use such thing as a single feint every day.
Also you don't need to move your mouse like crazy, only very slight movements are needed for that.
Edit: Also I have a very old office mouse with partly broken right button (If you press it in some places, particulary in front of the mouse, it doesn't react).
Edit2: And I usually release the left mouse button for a split moment which sometimes makes it even faster.