Personal Safety & Healthy Boundaries

The topic came up in our Counselor's meeting yesterday.  What do you do in your classroom guidance lessons to teach children about healthy boundaries and private parts?  EEk!  That topic is always so icky and touchy.  In the past, we've had our local nonprofit agency who works with sexual violence victims present this topic to certain grade levels, but now it is on us, as the school counselors, to teach the topic.  Although we are used to discussing this individually with students, the topic is more difficult with large groups because of the nature of the beast.  How do you say enough without saying too much?  Not to mention the parent permission component.  What is the best way to present this topic without scaring students, and on the other hand, how do we make sure we're not sending the wrong message?  For example, in the past, students would come to us following this type of talk and claim that someone had been touching them inappropriately.  It would turn out that someone bumped into them, or something of that nature.  We decided as elementary school counselors that we would like to have some type of lesson plan across the county so that we know that we are sending the same information to all students.  We also decided to send home facts and stastics about sexual abuse and notify parents of when the discussion would be and what materials would be used.  I've done some research, but I'm still not sure what materials would work best, and I've added a couple of links. I thought you all might have some suggestions!.  It had me thinking..

How do you talk with your large classrooms about personal safety and inappropriate touch?  What materials have you used?