A hotbox is an air-tight room or vehicle that contains one or more pot-smokers smoking one or more joints. The exhaled smoke and the smoke coming from the joint, unable to escape, circulates and thus is breathed in and is not wasted. Smokers in a hotbox may find themselves totally fucked beyond the point of speech after about 30 minutes. Hotboxing is an event that requires some amount of planning, but ensures optimal weed usage.

a sealed car with marijuana smoke in it; stay in a hot box to get more high

when u smoke in an enclosed area so that it holds all the smoke

When you smoke in an enclosed area(Car, SAUNA, Tent, small room) and the smoke stays in the area and you are contnuously breathing in smoke... the purpose is to FUCK YOU UP! Have fun.

the usage of a sealed off space for the purpose of smoking marijuana and not allowing smoke to escape creating a "hot box"

smoking marijuana in a vehicle or room until it is filled with smoke.