Dealing with a preteen who is experimenting in....awkward ways?

This is on a throw away because I am too embarrassed to post this with my main account.My daughter is turning 12, and she has started to experiment with her sexuality privately. I have no issue with this, it's completely natural! However... She has become fixated with her butt... dies a little typing it I again have no issue with what she is doing it's just how she is doing it... I have tried to explain to her that she needs to be clean about it, like only doing it in the shower etc. The problem is that she secretly uses foreign objects (pencils, small handled objects, the tail of an old dinosaur toy.... dies a little more) which she then hides (and yes they are still dirty when she hides them). How should I go about making her really understand she needs to be clean and not to use odd objects that could hurt her. I have also been trying to think of what kind of doctor to take her to about any of it. I have tried to explain all of this to her (many times) but it seems like she doesn't want to listen to me. The teenage stubbornness has started early! Any advice on ways to explain to her would be greatly appreciated.TLDR: Sexually awakening daughter into butt stuff and not clean about it.... HELP! via /r/Parenting http://ift.tt/2xthr4n