From my experiences, those first two things are dangerous for those children. Super dangerous. My husband and his family (8 kids, left unsupervised waaaay too often) experimented together like this and now as they have grown, their issues are all over the board, from sex addictions to lack of sex drives to prostitution to schizophrenia to drug abuse. Every single one of them say they were changed for the worst through their experimentation together as children. I think it's more common than most of us realize, but that doesn't make it a less impacting and traumatic experience.