Kneading the wrist and finger flexor muscles of the forearm pulling with your hooked thumb standing

Technique for the inner or medial wrist flexor muscles, such as flexor carpi ulnaris.

Stand over a table and place your hand, palm down on the table so your fingers point away.
Flex or extend your knees to adjust your posture and for optimal control over the technique.
Reach across the front of your body and forearm with your left hand and grasp your right forearm between the fingers and thumb of your left hand.
Place the pads of your fingers on the extensor muscles running down the outside of your forearm and wrap your thumb around your flexor muscles running down the inside of your forearm.

Start on the muscles at the top of your forearm, near your elbow.
Hook your thumb around the inside and back of your forearm so the tip of your thumb touches the ulnar bone, and the pad of your thumb is against the medial wrist and finger flexor muscles, specifically flexor carpi ulnaris.
Keep your fingertips hooked behind the extensor muscles at the back and outside of your forearm.
Pull your fixed hooked thumb into the muscles while simultaneously internally rotating your right arm at the shoulder and flexing your elbow as counterforces against your thumb pressure.

Increase the pulling action of your left arm by taking your left elbow forwards and keep your thumb in a fixed hooked position.
The tip of your thumb should point to the right and away from your body.
Do not lock your elbow in the fully straight position.
Keep your hand fixed on the table.
Keep your right shoulder over your right hand and your arm vertical
Work down the forearm from the elbow to where the muscles become tendons in the wrist.
The pulling action is not as strong as the pushing action of the previous technique, but it may be easier for people with inflexible shoulders.