Could you be charged with a crime if you didn't assist someone who died from auto-erotic asphyxiation?

Apparently if one restricts one’s air supply while masturbating enhances the experience. People have unintentionally died because they passed out with a noose around their neck while pleasuring themselves, and possibly this is what killed David Carradine and Michael Hutchence.

Imagine if your friend asked you to assist him in an auto-erotic asphyxiation episode to serve as his safety person who would remove the noose from his neck should he completely pass out at some point. Let’s say you begrudgingly assisted this person in this way several times in the past, but you refuse this most recent request. The next day you learn your friend died during his solo carnal act.

My question is what are the legal ramifications of this situation? I’m guessing it is unprecedented. Were you legally obligated to notify the police of your former friend’s dangerous actions? Could you possibly be charged with involuntary manslaughter as you’d assisted in the past and knew he was putting himself at risk?

For the record, this is a purely hypothetical situation and not a real dilemma with which I’m currently faced.