ah shit me and my friends used to do this, pre-social media. I remember one time in middle school recess, going out to the farthest corner of the playground with my friends, and we all did a thing where we took turns holding our breath while someone else squeezed our chest. I remember blacking out, hearing the pokemon theme in pitch darkness, and then waking up on the ground.
I don’t think we did it more than once (at least I didn’t). But of course, the crucial difference was that I was with my dumbass friends, so at least there was someone to run for help if someone didn’t wake up.