Kung Fu star David Carradine was found dead in a Bangkok hotel on Thursday. Police discovered him in a closet with cords tied around his neck and genitals, suggesting that he asphyxiated while engaged in a sex game. Is there a safe, proper way to perform autoerotic asphyxiation?

No. There is no doctor-approved way to strangle yourself while having sex or while masturbating. Indeed, cutting off oxygen to the brain is never a good idea. But there are ways to make this dangerous act slightly less dangerous: Do it with a trusted partner; set up a "safeword," commonly used in bondage situations, to signal your partner to let you go; don't use drugs or alcohol, which could make the strain that much riskier; and, of course, don't tie the belt or rope too tight. Some deaths by asphyxiation occur simply because the victim made escape too difficult—in one case, a man rigged it so he would have needed a bolt cutter to release his chains.

Autoerotic asphyxiation, or AEA, is typically performed in the following way: A man—the vast majority of AEAers are male—loops a belt or rope around his neck, attaches the other end to a door knob or pipe, and lowers himself into a controlled suspension. Sex or masturbation ensues. The pressure from the belt cuts off the flow of blood through the veins in his neck, causing blood to congest in the brain. Oxygen levels drop and carbon dioxide levels increase, producing lightheadedness and, for some, intensifying erotic pleasure.

When death occurs, it's usually because of pressure on a part of the neck called the carotid body, a small cluster of chemoreceptors located near the fork of the carotid artery. Pressure on the carotid body causes a discharge from the vagus nerve. This slows down the heart and can make a person pass out instantaneously. (That's why karate chops and the Vulcan nerve pinch target the vagus nerve.) Losing consciousness causes the person to go limp, which tightens the choke and decreases circulation through the neck arteries, causing asphyxiation. Rarely is there enough pressure to block the windpipe—rather, it's the lack of blood flow that causes death.

Can't you just hold your breath? Sure, but that's unlikely to have the same effect. Studies suggest that people who practice AEA do so because of the risk of flirting with death—not just because orgasms without oxygen feel good. (The bodies of AEA victims sometimes have evidence of masochism as well, like cigarette burns or mutilated genitalia.)

The first recorded case of autoerotic asphyxiation was Frantisek Kotzwara, a famous composer from Prague who died in 1791 while having sex with a prostitute. (She was tried for murder and acquitted.) Influential underground cartoonist Vaughn Bodé asphyxiated to death in 1975, according to his son. Stephen Milligan, a member of British Parliament, was found dead in his home in 1994, naked except for a garter belt and women's stockings, strangled by an electrical cord. * In 1997, a coroner called the death of INXS singer Michael Hutchence a suicide, but his girlfriend and some members of his family believed he died from AEA.

Statistics on AEA are hard to come by, since deaths by asphyxiation are often reported as suicide. But the FBI estimates that it accounts for 500 to 1,000 deaths a year. Closely related is the so-called "choking game"—the adolescent practice of strangling yourself or a friend—which caused 65 deaths in 2007.

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Explainer thanks Park Dietz of Park Dietz & Associates.

Clarification, June 11, 2009: This article originally referred to a garter belt by its British term, "suspenders." (Return to the revised sentence.)