I've talked to her in the past about how it does feel good and that that is normal and ok, but that because of these sorts of scenarios, it is probably best to find other ways of self soothing and relaxing before she goes to bed. I don't feel comfortable with sleep overs regardless, but even leaving her home with a babysitter, or a grandparent, I feel like this sort of behavior is something I'd really rather not have happening.both for her sake and whomever happens to walk in on her. She is doing it privately, and is sometimes conscious about it, but often seems to just do it without even thinking about it. Now that she is 6, she rarely has a problem with doing this in public, or around other people. My 6 year old daughter has been masturbating since she was a baby.
