The only thing I'd suggest you do is non-aggressively talk to the mother of the other girl and let her know that her daughter is "educating" your daughter about things that you don't want her to know. It's a case of TMI (too much information). This happens with young children sometime. My 8 year old took it on herself to give her entire first grade class a course in sex education when I was pregnant, simply because I had explained things to her. She also embellished a bit of her own. The teacher took me aside and told me and I dealt with it by explaining to my daughter that, like Santa Claus and the Easter Bunny, not every child is ready to know the "facts" at the same time. It fixed things. Let this mother know that her daughter is sharing too much information with others. Be tactful and remember that perhaps her daughter is embellishing too. Although it truly isn't appropriate for her boyfriend to be exhibiting his erections to her 9 year old daughter, err on the side of caution when approaching this issue and assume that it is either an exaggeration or accidental or the mother will jump right on her high horse about what is and what isn't your business. Make it clear that you concern is how it effects YOUR daughter, not hers.

If you know the mother enough to talk to her, then please do so right away. As the other ABer said, explain that her daughter is sharing way too much and most kids are not ready to hear about these things. If you do not know her and do not feel comfortable approaching, maybe slip a letter in her mailbox. I have to wonder what kind of message this mom is showing her daughter...."just have sex with anyone honey...you don't need to be married!"

no, the answer is no. if you have no suspision of any "foul play" going on. its not your bussines. people are really sex/naked-phobic these days. and all men (that i know of) often have erections in the morning... (but im sure you knew that)

I only hope the boyfriend is long-term and a proper 'substitute father-figure'. That way, maybe he's just acting in a 'natural' way, for him. If the mother is comfortable with it then maybe that's just their norm? Personally, I don't think that a girl of 9 ought to be exposed to a man who isn't her father in this way - and suspect too, that a natural father would feel more protective and have stronger boundaries. This really is a boundary issue. I'd talk to my friend about making stronger boundaries, maybe say that your own husband/boyfriend wouldn't act like that in front of a girl child. Myabe she'll get the message.