When a couple is sleeping "spoon style" and the one in front releases some toxic fumes, then raises and lowers the sheets ever so slightly propelling the stench up between the close lying bodies "the Chimney" and entering the nostrils of the one behind.
The example is obvious
by Monkey Boy August 03, 2004
Also known as a "Sun Roof", this is an overhead motorized portal designed to allow hot sick ass gases to escape the vehicle in a convenient and socially acceptable manner.
"Open the damn fart chimney man, your poop fumes are making my eyes water!"
by PixelPusher May 11, 2007