Once you conditioned your posture for practice or stage, your  can give your hands a little head start.

First, use your right index and middle fingers to sensitize the palm and fingers of your left hand. Outline the flexor side of each finger, feel the texture, warmth, trophics (are your fingers sweatty, dry), smooth or rough surface. Just "treat" one side to later compare hand differences.

Now, make a fist (left hand only). Slightly clench your fist intermittedly. (Apply no FORCE, but gentle pressure). Feel how the pressure builds up and how you release, again. With the other hand, apply a slight amount of pressure from the outside, so the bones of each hand are pressed inside their joints. This enhances the input to the brain.

Now, compare the feeling of both hands - "size", warmth, sensations like pins and needles, an increased blood circulation might be different in your left hand from the right one.

You can now tap your left arm with your right hand - or slide down from the shoulder to your hand with your right hand. Next might follow exercises like the visualization of a dwell in your upper arm, or "nerve mobilization for median and ulnar nerves".

Now repeat the series with your right hand - otherwise it might get jealous. Ready to go!!!