In BDSM, breathplay refers to the practice of restricting or controlling the flow of air and thus oxygen into the body of one or more participants also known as asphyxiation.
The rush that is a result of the lack of oxygen in the brain is the kick that people into this kind of edgeplay are after. The myth that a hanged man is coming at the moment of his death is common.
The adrenalin rush from the experience of real life danger and the dramatic notion of dying in someone's hands adds to this.
The techniques used to achieve this vary from scene to scene and thus the level of risk involved also varies. However most acknowledge that under most circumstances this practice is firmly within the definition of edgeplay.
Asphyxiation can occur as a result of restricting ones airflow by a rubber mask, a plastic bag, or by choking.
Especially auto-erotic breathplay can be considered as very dangerous and every year people die because of it. The often underestimated risk of temporary paralysis as a result of lack of oxygen in the brain is sadly a reason why people can't get up and die of asphyxiation.
Another risk is fractures in the trachea because of the applied pressure. If one is careful that is actually the least risk. But alas too frequently people accidentally die from the fact that our body tries to compensate for the lack of oxyen in the brain and this can cause the heart to flutter or because of the direct pressure on the nerves in the carotis that can cause the heart to stop. Aparently it is not easy to resuscitate these arrhythmias. This can occur as quickly as 10 seconds.
citations from www.helpdisk.nl - wurgseks