Doug Salomon
Obviously I do this when nobody is watching. I'm enough of of a weirdo without people seeing this.
This is one that I do when I'm bored. I tilt my head back against my hands for 20 seconds. Then, I tilt it forward against my hands for 20. I tilt it to each side (again using my hands to resist the motion) for 20 seconds each. Finally I turn to either side (pushing against that with my hands) for 20 and 20.