The image above shows the trailing wrist. Supination of the lead
wrist would cause this action. It feels like your wrists are rolling over
to close the clubface at impact, and produces a lower than normal trajectory.
Supination and pronation need to be practiced a lot before you put them into
play because of the timing involved. An "angled" hinging action is the safest
way to transport the clubhead through the ball because it relies less on timing.