When you are ready to use the waterbomb, spread the corners out, pulling on opposite sides to expose the hole in the top.  Blow a quick gust of air into the model to inflate the square shape. 

 

 Here is the inflated waterbomb, which is a handy decoration, and fun for a pet toy.

 
 
 Of course, to really understand the functionality of the waterbomb, you will need to pour some water into the hole in the top.  You can fill this up, and let it sit for a second so that the water saturates the paper.  It should be soggy, that way the paper will stick to your victim.

 

 Once both locks are completed, turn the model over.

  

 Valley fold those two flaps, and create locks. 
 

 

 Here is a complete waterbomb, ready for storage and transport. 
 
 

  

The loose triangle is valley folded over the pocket, so that it will well reach inside.

 
 
 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.

Everybody always told me not to get paper wet.  Not the newspaper, not the phone book, not the bills, not my textbooks, nothing paper could go in the bathtub.  Nothing liquid could go into the library.  Water and paper do not mix.  This is what they told me, and I think it explains my facination with origami that involves water.  Making paper involves allot of wet paper, the cup holds water, and the waterbomb transports water from your hand to your recipient..