Pretty much the greatest thing that has ever been thought of by anyone. It is when you turn off your car and roll up the windows and smoke Marijuana. The smoke fills the car and you breathe in secondhand weed smoke as well as the smoke you inhale from the bowl, bong, joint, etc. It works best when you use more than one method of smoking together, so you get really, really, really fucked up. Awesome.
Guy 1: Let's park behind the movie theater and hotbox this mofo.
Guy 2: Fuck yes. This is the funnest night ever!