The Involuntary Behavior of Musicians

I'm curious about where the line is between doing it on purpose or for effect. I've never tried to stop it from happening, so I don't know that I could turn it off. So I kind of indulge it when the,. when the, when the feeling comes over me that I need to do it. But yeah, that's a good question. With an involuntary behavior like that, you know, how much of it is controlled and how much are spontaneous? "It feels good," says singer-guitar player John Cusack. He started playing guitar at age 15 after his parents gave him a turntable.