Yes, Toto, we are in San Francisco. The sex coffin idea was conceived by a team of conference organizers led by a peculiar dude with frizzy hair named Johannes who hails from Vienna (where else?) and dresses all in black. The event was a statement on the diminishing realm of privacy in the age of the internet -- that, for instance, you can just be minding your own business, going to Poundtown with your honey in a coffin buried underground, but really the whole thing is captured via a infrared camera and projected onto a giant screen outside for dozens of rooting spectators to see like a macabre Paris Hilton sex tape. Hot.
To prepare, the team built a wooden double-wide sex coffin, had a dumpster full of dirt hauled onto Howard Street (not an easy feat, Johannes informed us) and defiantly set it down across the street from a church. A couple of gravediggers excavated a hole large enough for the coffin. They then asked for volunteers to go down (in more ways than one) to join the six-foot-under club. This being the puritanical and litigious United States, the couple first had to sign a release stating Arse Elektronica was not responsible for any untoward health issues that came up down there.
The first couple up was a very normal-looking hetero pair that wouldn't be out of place having Sunday brunch at, say, Tartine Bakery. They christened the coffin with the night's first copulation, broadcast in an eerie green night-vision hue up on the wall. The effect was something akin to an X-rated Blair Witch Project with a steadier hand on the camera. And the cock.
A random passerby stopped to take in the spectacle: "How long are they going to be in there?" Don't ask questions, dude, just go with it. Later on, two ladies who claimed to be sex workers got it on with a harness. One of the ladies has since written up the experience.
After the first couple was finished, the organizers pulled back a cloth of dirt draped over the coffin, opened the lid, and voila, the couple popped out looking very sweaty and very satisfied, garnering wide applause. Johannes presented them with a "Six Foot Under Club" certificate, onlookers shouted "Congratulations!" and the next couple descended to get it on. Corpse style.