She was my bestfriend she was in 2nd grade. A kid not even a teenager. She really did something very unusual and too sexual even for adults to do

So I was her bestfriend too . We sat talked and lots of laughs. We were back benchers . Our place was at the last bench . Girls and boys rows were seprate . But due to some issues our teacher made few boys to sit at last two benches which were empty behind us. She started behaving weird . Often ignoring me. She started talking to those boys well I was a kid so they were my friends too. But something was not right my bestfriend was too much into them she ignored me all the time.... One day I saw her removing the underwear under the skirt and I saw boys from behind touching her down there hips to vulva . It felt odd as a kid i dint knew what is sexual or not but it did felt groos for those boys to touch something we girls use for peeing. She laughed and always removed the underwear and they were 5 guys each taking turns to touch her . She dint even told me about what she was doing . Just sitting beside me and taking off the underwear. It was very bad to see that happen. One day everyone left the class at the leaving time and I was waiting for her to come with me. While the other were facing towards the exist and moving away she removed the pants and exposed her parts to the whole class no one saw exepct me and those guys as others were leaving. It was insanely gross. One day my teacher forced me to sit in the boys rows. She picked up few students from last three benches to make them sit at boys row. So me my classmate girl she was girl and 2 boys were selected to sit at other row. So we sat and the guy beside me literally a kid , he was my bestfriend's friend too who touched her. This boy this little boy unzipped his pant and shown me his Lil penis which wasn't even grown as a kid . It was erect that's what most shoking part is. He told me to touch it . I was very scared too scared . Then the boy beside him he was a guy. He told that penis boy to stop doing gross things. I instantly felt like this other boy is protecting me. He made me feel safe glad there are some kids that are good. Even kids aren't safe now. What happened to me and in the class was insanely distrubing. I wonder who teach them these things, were they just curious , or someone adult or was teaching them these they all were just 8 yr old..iam still very much shocked now I can't understand who taught them these. And even if even someone did teach them these why would they donand how come a kid could enjoy these? When I learn about sex for the time I was obviously grossed out. Edit: why are people making fun of this? This issue is a real problem and it's very concerning. Stop making fun of something very sensitive