You’re a genius, Kevin! The next Hermeto. So this is a way of controlling the lever, the end of which you’re now not just pushing down; the end of your thumb is impeding the downward motion. But here’s what I just discovered: it’s even easier to do with your thumb on the end of the key after you put your Yamaha back together again. So we’re applying friction at the end of the key. This also works with the black keys, though it’s a bit trickier. For an “all thumbs” guy such as myself, this opens up real possibilities.