Unhook, and bear off the wind with lots of speed. Slide the rear hand a little forward on the boom so it is near the center. Experiment with the exact placement of your rear hand as you gain more experience with this maneuver.
Lean forward and bend your knees. Rake the sail back so the clew comes toward the rear of the board while tilting the mast forward and down toward the water. Now, let go with the front hand.
The front of the sail will fall flat but your hand will act as a balance point and support.
Keep the knees bent and your body weight forward as the board approaches dead down wind.
Notice my weight is still forward and knees bent. The foot of the sail is pressing against your shins.
The sail is completely flat and there is no power. Notice again, the foot of the sail is firmly pressed against your shin.
Let the clew rise a little higher than the boom head to really bone-out the move. Grab the boom again.
As you head into the new direction, bring the mast vertical.
Your body now comes vertical and you are pulling with your front hand so the sail becomes vertical.
The sail is now vertical and your weight has shifted a little back as you exit the belly of the jibe. You are sailing out of the jibe clew first and power has returned to the sail.
Now let go of the rear hand and let the sail rotate.
Grab the sail on other side for your new board direction.
Switch your feet, adjust, trim, and sail away.