Wait.. if you need to push a button and then have to get it somewhat close to your mouth to record an audio clip, why not just have a watch app? Pressing the button is still a two-hand thing. Or did I miss something?

You put the ring on your index finger (and likely have it rotated so that the button is pointing to your thumb) and then press the button using the thumb on your same hand. That allows it to be one-handed.