How do you get the dexcom platinum sites to stay on?

I just started on the dexcom today and the sensor started coming off after a few minutes so they put a dressing over it and now tonight that dressing is lifting off. How do you get the sensors to stay on? I was told I could take a shower or a bath but now Im scared to that its going to come off and they are too expensive. Please help..

There are several good discussions on this in the Dexcom group.
http://www.tudiabetes.org/group/dexcomusers

http://www.tudiabetes.org/group/dexcomusers/forum/topics/skin-tac-wipe-and-tacaway-question
http://www.tudiabetes.org/group/dexcomusers/forum/topics/not-sticking