Valley fold the loose edge so that it fits inside the pocket.
The loose triangle is valley folded over the pocket, so that it will well reach inside.
Slide the loose flap into the pocket. This is the "lock" of the waterbomb.
Tuck the flap into the pocket, creating a lock. A good lock is one that will open once it hits the target, opening the model, which should stick to the victim. But it needs to be solid enough to hold the water during the flight.
Valley fold the opposite side, and create the same lock over there.
Valley fold the other flap on this side, and create a lock on that side, just like you did here.
