"As I told you before, I am SURE that abuse can be ruled out."
There is no way you can be SURE without professional help, unless you are psychic...not to mention you already told us she HAD been abused by non-existent "Anna"! The story keeps changing.
First, I hope we can agree that mothers are not psychic and do not magically "know" when abuse has taken place; if they did, we would have ZERO molestation, wouldn't we? Yet, millions of children are abused everyday, right under Mom's nose! How do you account for that?
Also, I'm sure everyone means well, but there is NO way to tell if someone is a "good" mother or not, based on a few postings on a message board.
But here is the evidence:
1) Mom herself describes her 4-year-old's self-gratification as obsessive and compulsive; THIS is the key! No one says self-gratification is abnormal, per se. It's the compulsivity that keeps her from children's normal activities (per her own mother!)that is alarming. Mom is so alarmed that she is compelled to write to a message board about it. Yet, she seems more interested in stopping the embarassment it causes her than getting to the root of the matter. You don't set "limits" on compulsivity. That is underestimating the extent of the issue here.
If this is self-comfort only, what the heck is going on in her life that she needs it on a compulsive basis? SOMETHING is going on here. IF she has been molested, I promise her actions will become even MORE embarassing to Mom, as we know what often happens to little molested girls when they grow up.
It's the COMPULSIVITY Mom herself describes that makes this abnormal behavior, not occasional self-gratification itself. Definitely not normal.
2) The non-existent little friend, Anna (which is a name commonly taken by nuns, by the way). Since there is apparently NO Anna, then who is it SHE confessed to being touched by? I doubt she made it up, but may have gotten the name wrong. It quite possibly IS an adult.
3)SHE ATTEMPTED TO ENGAGE AN ADULT IN playing with yourself, spanking the monkey HER! This is truly learned behavior. In all the excerpts regarding normal self-gratification in children, incidents of "playing doctor" with peers and rubbing oneself is common. But nowhere is this sort of boldness with adults described in children who haven't been molested by an adult.
Like many women, I'm afraid you don't want to find out it might be a family member you trusted. Anyone overly interested in bathing her, dressing her, spending "alone" time with her?
I do believe it is incumbent on a good mother to be sure; how can YOU know when millions of mothers didn't? You can't. You don't. Your child's well-being is more important than any embarrassment her actions are causing. How will you feel when you get calls saying she is doing the same thing to other children and adults? Now THAT will be embarrassing. If it's due to molestation, no "limits' will be enough.