Learn how to make a homemade waterfall bong for fun in simple steps. You will need: a corkscrew, steak knife, 5/16 socket, chopsticks, weed, 2 liter bottle and a lighter. 1. First make a small hole on the cap using the corkscrew and make it to fit the 5/16 socket using the steak knife. 2. Now make a hole at the bottom of the bottle using the knife. 3. Put the weed in the socket and fit it to the bottle cap. 4. Fill the bottle with water, close it with the lid while blocking the bottom hole with your fingers. 5. Finally flame the weed carefully and enjoy.