Stability is the key to good motorcycle handling and being a confident, controlled rider. There are several different stages of stability: 1 You're stable on the motorcycle and the motorcycle is stable underneath you; 2 You're stable on the motorcycle but the motorcycle is unstable; 3 You're unstable on the motorcycle but the motorcycle is stable; 4 You and the motorcycle are unstable.
The ideal is a stable motorcycle and rider. The worst is an unstable motorcycle and rider. This can be so much of a problem that you could find yourself in the hedge in the blink of an eye. If the motorcycle is unstable but you're stable, the motorcycle will regain its composure very quickly indeed. Why? Because you let it. If the motorcycle is stable, but you are not you could quickly find yourself in position 4 and heading off the road.
For example, a headshake or tankslapper is just about as unstable as a motorcycle can be. The easiest way to get out of it is too relax and let the motorcycle do what it needs to do underneath you. However, to relax the upper body, the lower body needs to be locked into the motorcycle. This applies to all types and styles of motorcycles, from sportsbikes to motocrossers to tourers. If your lower body isn't locked in then you'll be hanging on too tightly to the handlebars and you'll end up very tired at the end of a ride. This is one of the major causes of motorcycle handling problems that a motorcycle has to deal with, and no amount of steering damper, suspension re-valving, or set-up will cure it.
If any parts of your body should ache after a spirited ride, it should be your knees and legs if your shoulders, forearms, hand, neck, or back are giving you stick, it's a sure sign you were holding on too tight.
Squeeze the fuel tank with your knees and see how much easier it is for you to relax your arms. If you hang off when you corner a motorcycle then learn to lock your leg into that indentation in the fuel tank. This may mean you have to look again at how your foot is on the foot peg, but do whatever it takes to get your lower body stable, locked, and loaded.