The word 'blowtube' has gained common use on college campuses to refer to a tube of some sort (i.e. cardboard from a paper towel roll or a 20 oz. drink bottle with the bottom cut out) stuffed with dryer sheets. It is used mainly in non-smoking dorms to cover the smell of burned marijuana. Smoke is blown through it in order to lessen the smell. Most effective when combined with a towel at the foot of the door to prevent any smell from escaping into the hall.
Also known as a "doobtube."