6 year old girl classmate of my daughter being inappropriate in the bathroom with her. don't want to under or over react. advice please?

a few weeks ago my daughter tells me that her bathroom buddy (we'll call her green) peeked in at her through the bathroom stall while my daughter (blue) was peeing. when she told us we had another talk about privates and for her to tell green to never do it again. she says it hasn't happened since.today my daughter tells me that green told her she'd bring in an "lol doll" (just some popular doll) for her and give it to her if blue pulls down greens pants in the bathroom stall. she told me she said yes to get the doll but she was not going to do it "cuz she doesn't want to see greens privates." we had another, more lengthy talk about her privates, other peoples privates, what is ok, and what is not. she understood everything i said and assured me she would never do anything with anyone else's privates even if she wanted to. she understood she is too young for that and that kind of stuff is totally ok for humans, but when they are much older.i then asked if there was anything else green has said or done that was "weird". she told me they play this game where greens fake name is max and blues name is penelope and max is the boy. she said they usually just call each other these names for fun, but green asked blue to come in a stall and when she did green asked if blue "wanted to see how boys pee." blue said no and left the stall.I'm not sure howto handle this properly. Blue says it doesn't really make her feel uncomfortable and green and her are just really good friends. it is still inappropriate though, and i'd like to handle this as tactfully as i can.thinking about talking to greens mom tomorrow, but do you guys have any idea if im under or over reacting? i know kids are curious. via /r/Parenting http://ift.tt/2zlwIWf