I wouldn't worry about it. Don't do it again, but don't worry about the one time. I think the risks of this kind of thing are mostly when it is actually being done. Worst-case scenario, the person squeezing the neck does it too hard or too long or in the wrong place and actually causes brain damage or death. And of course there is the risk of being injured while falling to the floor. But it seems that none of these things happened to you, so I wouldn't worry. Also, those are probably very extreme examples of what could happen and are probably very rare. I suppose if you did it often enough (especially if they squeeze the veins but not the arteries, so blood can get into the head but can't get out) it could put undue pressure on the arteries in the brain and if there was a weakness already there it could cause the vessel to rupture. So you're right... it's probably not the best activity to entertain yourself with on a nightly basis, but I wouldn't worry about the one time.