Ki

From "Zen Guitar":

Musicians can project their ki outward through sound. When you pick up the guitar, imagine your music flowing through the instrument like water through a hose. Spray the water to the sky.

I like this concept. The idea of ki or "life force." I remember one of my friends (who used to teach voice) told me once that instead of struggling with a high note---which means that you tighten up and try to press the note outward.

Instead you imagine the note spinning, not so much being propelled, but spinning inside your throat and then higher into your head. As though you are breathing it in. Not forcing it out.

Breathing in of the life force maybe? The opposite of pushing it outward (though when I play an instrument I definitely feel a force of energy moving through me---it's better than almost any other sensation in life)