Welcome to the STD forum. Initial response, only to the title of your question before reading anything else: There is no STD risk from body rubbing. If a bare penis (i.e. no condom) doesn't get inside someone's vagina, rectum, or mouth, generally there is no STD risk. That's why they call them STDs.
Now I have read the question itself My reply is unchanged. You are not at risk for any STDs and should not get tested unless you have had real STD risks. Here is a thread that goes into the scientific reasons for this response. Start reading with the follow-up comment dated December 14:
http://www.medhelp.org/posts/show/1119533
Regards-- HHH, MD