Thanks for the comments. I've checked my daughter for a yeast infection or sny type of irration and she is fine. She tells me that the reason she does it is simply because it feels good. It upsets me only because I don't want the other children making fun of her in class. She doesn't seem to care that others catch her or that she is not alone.
I don't know what else to do.
Thanks again.
My daughter, a 6 year old, also has this problem. Make sure she does not have a yeast infection and make sure she does not have labial adhesions (labia grown together). There are safe & easy treatments for each.
You are doing fine. Your guidance to your daughter is very sensible. Be sure that there's no irritation which might be exacerbating the problem, and continue to set limits on her touching herself when she's in situations which are not private.