It's called stimming (self stimulatory behavior...it is stimulating to the nervous system). Everyone does it to some extent or another. Twirling pens, hair, chewing gum, chewing or clicking on pencaps, rubbing hands together, picking at fingers, biting nails, etc. Bouncing a leg is a very common one. I do it too. My kids are both autistic and they have various stims. One runs his hands together so often that he has red patches on his palms. It doesn't hurt him, though.
Your husband is creative, huh? Not surprised.
Stimming is an unconscious release of nervous energy/anxiety. It's healthy and should not be suppressed.