BDSM
I'm sorry that happened to you. Choking is a specific art and must be done with knowledge and intention so as to not cause damage. It can be very dangerous otherwise. I engage in erotic asphyxiation sometimes under the right circumstances only because I am highly experienced and have been into it as a giver and a receiver for six years now, and thus understand both sides of the experience very well. But erotic asphyxiation needn't cause any damage to the neck when done properly and if someone is being that reckless, I would consider asking them to either not engage in choking activities in the future without some further education on their own behalf so they don't hurt someone. 
I'm sorry that happened to you. Choking is a specific art and must be done with knowledge and intention so as to not cause damage. It can be very dangerous otherwise. I engage in erotic asphyxiation sometimes under the right circumstances only because I am highly experienced and have been into it as a giver and a receiver for six years now, and thus understand both sides of the experience very well. But erotic asphyxiation needn't cause any damage to the neck when done properly and if someone is being that reckless, I would consider asking them to either not engage in choking activities in the future without some further education on their own behalf so they don't hurt someone.
To do a blood choke, you need to find the wind pipe (a tight column running down the center of the neck) then you move your fingers to either side of that, generally right under the edges of the jaw and you find the pulse, that will be the artery. Pinch it, but not against the wind pipe. 
Air way chokes are what is normally thought of as choking but can be very dangerous if you apply too much pressure to the wind pipe. This can be avoided by covering the mouth and nose with a hand instead or by putting a plastic bag over the head.
Chances are, you want to do a blood choke but without passing out.
