Hi Flogfan,
"Erotic asphyxiation" can fall into the category of a risk aware consensual kink (RACK). The more you know, the more aware you are of the risk and yet you may still make the decision to try it out for yourself.
-- Comment removed per Mad Lews's observation in the next post. --
When doing research, I like to start with Wikipedia,
then follow the links they've provided for more information.
http://en.wikipedia.org/wiki/Erotic_asphyxiation
All the best,
Ruby