Yes a real pincher, a bunghole pincher :) Seriously I can understand people have trouble with that one since you have all those routes to make, and you can't afford to make a single mistake or you will kiss death right on his lips.
If I were to mess up on Luigi's Purple Coin Chaos, it'd be when I have 85 coins. This is when I usually find myself crossing into a clone or two while grabbing the rest of the coins, since the clones are usually clustered together near the beginning due to all kinds of zig zagging requirements (upon my return) due to the way the purple coins are spaced apart.
Last night a mouse actually bit or pinched my big toe on my right foot while I was online. I nearly jumped up in shock, haha. It was sort of hilarious watching me act like a little girl over a freakin' mouse.