The other night, my daughter started saying something about a secret about her and her cousin, but that she couldn't tell me. I finally convinced her to tell me. She told me that her cousin and her lay down and put where they pee pee together. I didn't freak out, but I took her into her room, away from her father, and asked her a couple of questions about it, like where did they get that idea (her cousin), and where did he get that idea (from him). I told her it wasn't ok, and that if it ever happened again, that I needed her to go find her grandmother or me. She is 5, and her cousin is about to turn 9. Her cousin was bounced around a lot when he was young, and his mother had him in situations that were enough for my in-laws to take him away from her. While I know that kids are curious, lord knows I was when I was her age, his mother just had a baby girl, and I am unsure if I should say something to his mother. She doesn't exactly like me, and even my husband was quick to not believe my daughter. I feel like I should say something, but probably not to my sister in-law, because I think she will only make matters worse. My stomach has been in knots over the decision, and I am stuck in limbo.
Any advice is appreciated.