I read this post a couple of days ago and back then I kind of shrugged and thought it was hard to tell. But only now came to me all of a sudden the question about your mother: how did she handle that? I mean, what you describe doesn't sound necessarily like abuse but certainly like a little bit too close for comfort. And a mother should really see that and be really concerned about it. But the way you describe it, it looks as if she just let it happen?
Oh, and did this nudity thing go on later as well, when you were 12, 15, 19?