Stand with arms outstretched to the side, palms facing down.
Internally rotate the upper arms as you bend the elbows and touch the fingertips behind the hips or lower back.
Gently slide the hands up the back as possible, pressing the hands together as you go.
Form tips
Ideally the hands will end up between the shoulder blades, but be mindful of the wrist and finger tension, and the shoulder tension if you have tight shoulders.