Mom's of Older (5+ yr old) girls....

 My daughter who is nw 12 starting humping the bed when she was about 2. My first response was that something had to be happening to her at daycare for her to even know about toucing herself down there to experience pleasure. I took her to the pediatrician and she assured me that it was normal even at 2. She probably "accidently" discovered that it felt good and as humans continued to do what feels good. I just told her that it was something that she needed to do in privacy in her room. I left it at that and if walked in on her I just turned around and walked away. Its important not to make her feel like she is doing anything wrong, we are all programed to do things that feel good. 

Like others have said, I think the bahavior is pretty normal. Somebody probably does need to talk to the 12 year old about boundries though - she is not in charge of teaching younger children things like that, no matter how much she herself enjoys it.
The fact that she was embarassed to be caught doing and  talked to about it indicates to me that she knows it is something personal. She is old enough to understand that, like picking your nose and scratching your butt, there are some things you do in private only. Her mother needs to be responsible and have that talk with her and reinforce that, although maybe the way her aunt said it might have hurt her feelings, she was correct in telling her that that is not an acceptable behavior for anytime, anyplace.

THANK YOU!!!