Return to Carb (thing)
|Pothead slang (from carburetor) for a small hole found either on the side of a bowl, bong, or other drug paraphernalia. Also sometimes referred to as a rush hole.
When smoking, you light the marijuana and pull gently with a thumb on the carb. When you are ready to clear the chamber (remove all the smoke from the smoking implement) you remove your thumb from the carb and continue to pull.
This process serves to provide an intermediary state for the smoke between the weed and your lungs. This allows it to cool and provide smoother, but still very potent, hits.