Your not meant to be choked til you pass out a friend is meant to bear hug your lungs from behind then you signal them to stop and then you slowly blow the smoke out. I did it once and had deja vu and saw my mother and grandparents at our old house. It was strange I saw it through my own eyes and I would have been about 2 or 3 at the time it was crystal clear though. Then I woke up a few seconds later and didnt know what was going on for a few seconds, it put me off doing it again.