Paddling in reverse procedure is much the same as switched forward paddling and can moreover use for lessening speed in waves or when coming to rescue. Since you will most possibly want to paddle in reverse fair many meters, holding the balance is much important than the style.
If your kayak is prepared with a rudder, paddling backward may be difficult. In such case press both foot paddles to hold the rudder directly. Also, there may be a chance for stern- heavy kayaks to act in a different way while paddling backwards; the issue may overcome by leaning forward within the cockpit to raise weight from the stern.