You don't really need to do this. Just fold the front of the diaper flaps together. Next roll the diaper up from front to back. Lastly, roll one back tape over whats left and keep rolling until you come to the tapes on the opposite side. Tape the diaper back onto its self, and it will be somewhat sealed into its self.
That's just it though. If you roll the diaper up as I describe then the full mess will be fully contained within the backing of the rolled up diaper. There is no need to extra wrap or double back them if you do it right.