To do this stretch the stretcher is lying on their back with their elbow straight and their wrist and fingers extended as far as possible. the partner places their palm against the stretchers, matching thumb to thumb and fingers together with their other hand stabilising their forearm. The stretcher should try to flex their wrist and fingers towards the ceiling, don't forget to stretchthe thumb as well. The strecher should breathe in deeply and on the exhale extend their wrist and fingers again back towards the floor. The partner can gently push on the stretcher's fingers to deepen the stretch.
Images from www.wikipedia.com