It's actually one of my favorite things, although I try to only practice it rarely. I'd been interested in various forms of asphyxiation since I was an adolescent, or possibly even younger, when I would see strangulation or hanging scenes in movies. One of the earliest I remember is some made for TV movie where some lady gets knocked out and finds herself locked in a walk-in refrigerator, with a noose around her neck that was tied to her legs which had been pulled into a hogtie. In theory, her legs cramping from being in the cold would cause her to slowly strangle. Sadly, she escapes and ultimately catches the culprit, but some of her friends or sisters are killed in this way before then.
As a kid, I'd sometimes try to hang myself from the stairs to the basement, although I was a bit too tall already for it to be effective, as I was looking to be in full suspension. Once, I tried something that was, in retrospect, pretty stupid. I tied my ankles to the footboard of my bed, then had some slip knots tied to the posts of my headboard. I put a plastic bag over my head and then put my hands through the slip knots and pulled. Fortunately there was enough slack on those ropes, or that would probably have ended up rather poorly. Looking backward, I'm not even sure that I had learned to masturbate at that point, so I'm not even sure why I was doing it. Seems like it would have been a waste.
Throughout university, I would attempt various autoerotic asphyxiation whenever I got the chance to be alone. I had a single dorm one year with a strong garment rod screwed into the walls above where I moved my bed, so that got some good use. In law school one of the apartments I lived in had a fire ladder in the below ground family room to reach the ground floor windows, and I hanged myself from that a few times. A later apartment had a surprisingly strong hook screwed into the ceiling.
Lately I still do some things, mainly experimenting. I have one of those Power Tower pull-up stands to use, and it works quite well. I've found that no matter how I pad my neck, a 3/4" cotton rope noose bites really hard and always hurts, even if I'm supporting half my weight with my arms. There's a type of noose that I found on another site that's made by stretching out a t-shirt [please note: that site says, and I will reinforce that it's extremely dangerous to use it, as it can induce unconsciousness extraordinarily quickly] that I sometimes try. For some reason, I find that it does not hurt nearly as much as the rope, and probably due to being high on adrenaline or some other hormones during the preparation for a session, practically doesn't hurt at all. It is with that noose that I have come the closest to passing out. At one point I actually tied it off and tried full suspension with it by lifting my legs, but I could feel that given just a few more seconds, I'd probably pass out and die. With half-suspension, I still begin to feel faint very quickly, though thankfully not so quickly that I can't rub one out in time. It did leave an extraordinarily set of bright red welts on my neck, but those thankfully disappeared in about 4 days.
I have the feeling that my experimentation will likely end in a premature demise one of these days. If I knew the world was about to end, I think I'd just try taking it all the way. I'm a bit new to the site so I'm not sure how other people here feel about this, but when I play by myself like this, I tend to enjoy crossdressing with it.