So many of these are horrifyingly familiar…
At secondary school in the late 80s/early 90s, our (single, male) form teacher used to invite us round to his house and ply us with alcohol from age 13. On one occasion took us swimming (we were swimming, he was watching) as part of the outing.
Same teacher used to take us on nights out from age 15ish, would let those who had turned 17 (but not yet passed their driving test) drive his car home (with the rest of us in it) when he had been drinking.
Once aged 14, I’d stayed behind to wait for a concert/play rehearsal - there were a few of us hanging around and I ended up chatting in the teachers’ study with two boys (aged 15 and 16) that was friends with. It got silly, they started trying to tickle me and when I tried to leave there was a tussle which ended in 16 holding me down while 15 started to take off my clothes (!). I yelled out, teacher walked in, took one look at the situation, said “now now boys, play nicely”, walked out and shut the door - basically gave them the green light.
To this day I believe the only reason it didn’t go any further is because when I screamed again another boy from my year came in to see what was happening - everyone froze and suddenly I was being helped to put my clothes back on while the other two laughed it off as “only joking, no harm done”!