It is mandatory at my school to get choked out (really out) at least once to let you know what it is like. I decided to get mine out of the way. We would sit facing the instructor. The person behind me applied an RNC(blood choke style, not the Dan Severn), I took some breaths and let him know I was ready. I was out within 5 seconds. It was video taped, so I saw myself. My eyes rolled in the back of my head and I twitched and bucked for about 2-3 seconds. I was out around 3-5 seconds, but it felt like days. I woke up and didn't know where I was at first, then all of the sudden, I came out of the "fog" and went and sat down. It is a really strange experience.