Requiring two people but works best with three. There is a Furnace, a Chimney, and a Sweeper. The sweeper prepares the Chimney by rolling them on their back feet first so their ass points up in the air and gently inserts anal beads into the Chimney's open anus. The Furnace prepares the smoke by ripping a massive bong load and then blows the load into the Chimney's open asshole, Loading the chimney. The Furnace then vigorously rips the anal beads out, forcing the bong load into the Sweeper's mouth.
Dan: I can't believe how long the smoke trail was last night.
Steve: Yeah, the London Chimney gets you high, bud.
When you're comfy and wrapped up in a blanket in bed but leave just a little opening for airflow and proceed to blast the nastiest most egrigious fart known to man straight through your little exhaust hole and right into your face
Tom: Hey man, I was laying in bed and had the nastiest fart. It came straight through the opening I left in my blanket and suffocated me.
Al: Sounds like you London Chimney'd yourself, mate. Why?