We are only human. But what happens when you need three parts playing at once and 1. both hands are tied up playing other parts, 2. you are trying to reach a key on another manual and you can't hold onto one note in one manual and reach another note in a different manual, 3. your nose won't reach to play a holding note. I have got a little known trick that might just help and I learned it from my years of playing piano. I was working on the 20th Century Fox theme for the begi