The first word that comes to mind is intensely. Gravity bongs work by using suction to build a giant cloud of smoke and then utilize pressure (created by water and gravity) to propel this cloud of smoke directly into your lungs.
1. Fill chamber (the open-ended vase) with water to the top of the leaf logo
2. Insert the bottle-looking piece into chamber and pack bowl with grinded herb
3. Light bowl and slowly pull the bottle up. You will see the bottle fill with smoke
4. Stop pulling up before the bottom of the bottle leaves the water, then remove the bowl and replace it with the glycerin coil
5. Put your lips to the coil and slowly press down on the bottle. This will rapidly send smoke from the bottle to your face
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