**TRIGGER WARNING** SEX ABUSE

I apologize for the formatting, as I'm on mobile. However, I'm reaching out for advice, input, and resources. I'm at a total loss.I have two kids 3yr old boy, 18 month old girl. We live in a small apartment complex and the neighbors a few doors down have two kids that my kids play with every single day. They are a 5yr old girl and 3yr old boy. We will call them 5G and 3B. Then a few more doors down is another little girl who is here half the time (shared custody) but when she's here she's always out with the kids. We'll call her 3G.Us parents usually sit on the porch and chat while the kids play. They have a "fort" in the back yard (where we can't see from the porch but there's no real danger back there.) The kids like to play make believe games back there, usually "house" where my daughter is the baby, my son is the dad, 5G is the mom and 3G and 3B are the kids.******* TRIGGER WARNING *******Today was just like every other day. The kids were playing house and the adults were chatting. I stepped inside to make mac n cheese for everyone while the kids played around back. The other parents are still chatting on the porch and what not. Later that evening my kids are inside we do dinner/ bath/ books and are putting our son to bed when he tells my OH that, "5G 3B and 3G licked my butt and penis." I came in the room at this point and my OH asked DS to repeat himself, and he did. Then I ask a number of questions, trying to stay calm. The last thing I want is for DS to feel shame for something like this, because no 3 y/o knows about stuff like this.So apparently when I stepped in to make lunch, 5G pulled down DS pants and told the other kids to lick his butt and penis. I asked DS "Why?" And he didn't know. 3 is still kind of young to articulate things like this, but he did tell me that he didn't say anything and kind of just let it happen. I'm guessing he was very confused and just kinda checked out. He said that all the kids did it. And shortly after 3G had to go to her other parents house, so I'm sure her parents don't know about it.But where do I go from here? I'm really close with 5G/3B's mom, so I'm planning on addressing it. But what's a constructive way to address it/ handle this?I had a long conversation with DS about privates and that we need to tell a grown up immediately if someone tries to look/touch anything covered by his underwear. I also reinforced that I was proud of him for telling us about this and that he did a really good thing. I let him know that it's okay to say "No" if someone does something that doesn't make you feel comfortable. But what else needs to be addressed here with him?HELP! via /r/Parenting https://ift.tt/2MGcJZA