Instead, you can practise a type of meditation where you focus your mind on the activity of riding.
You need to clear your mind of other distractions which is pretty easy in the closed-off atmosphere of a helmet.
The second step is to lift your gaze.
Hunched shoulders also tend to make you drop your head and shorten your focus.
The shorter your focus, the less time you have to react to road conditions, sudden corners and other hazards.
So lift your head and make a conscious effort to look further down the road and around the corner.
The third step is to physically relax your arms.
I recall a professional rally driver once showing me his technique for un-hunching his shoulders: He basically flapped his arms for a few seconds like he was doing a short chicken dance while he was driving.
You can do it on a motorcycle as well.
As your arms relax and your shoulders drop, your arms will naturally bend so you have more control and can more easily counter steer.
Try these steps the next time you feel your shoulders hunching up and your vision becoming fixated on where you might crash!