He might not be aware of it. So I'd definitely keep my eye on that. He thought he broke it or something. I had the same problem. It's not too young and it's perfectly normal. I will say my 5 year old son does the same thing and I have just had to explain that what he is doing is a private thing and he needs to go to his room or the bathroom and shut the door and i have even talked to him about not letting anyone else touch him there and tell me if they do. A lot of parents just try to correct them like it is a bad thing, which it is not.
In younger children this is most commonly seen as the child will hug closely a pillow or stuffed animal and rock back in forth.
Is it normal for a 9 year old to masturbate?
David MageeDr. However, that is not an exact blueprint of all children. It is possible, but not really normal, most kids don't get into this habbit until about 12 - Answer Questions I said John 3: How to give my 9 year old son the talk about sex?