Cover this hole with your finger and fill the bottle up. Uncover the hole out the bottom, and as the water drains out, the smoke will be drawn in. Keep the bowl lit and let the water drain out, and by the time you're done you have a 2-litre bottle full of concentrated smoke. Just suck from the top and uncover the hole at the bottom to hoot. This is also an extremely efficient design, as very little smoke can escape.
Knives are a rather complex method of smoking dope, but also a very powerful and efficient method.
You heat the knives to the point where they're glowing red. Plumes of smoke will come up into the bottle, which you then draw into your lungs. This can hurt your throat like hell, but it works beautifully. It's also the most popular way to do hash, and a reasonably good way to smoke hash oil. This is a really entertaining way to smoke dope, and also a pretty good party trick.