[Raleigh]

I don't know of a source of the felt piece, but they're not too hard to make with a sharp X-Acto knife. You should be able to buy felt at a craft store or fabric store. The original felt is not very thick. The felt I used was a bit thicker and stiffer, just because I had it lying around.

The hole in the felt should be just barely big enough for the push button to slide through but too small for the flange at the bottom of the button. That should trap most of the light that leaks around the button. It might solve your wine-colored projectile problem, too. If not, you probably want some kind of adhesive that stays tacky or gummy to hold the button on its shaft. I'm not sure what kind of glue that would be. Maybe ask at an art or craft store.

Or maybe try to shim the button on tighter with a tiny bit of paper or something.