I did wear mine out in the heat and didn't have any trouble with them. You have to be very careful not to use any lotion of any kind on that area of your body or they won't stay in place. In fact, it is best to wash and pat dry the area before putting them in place.
Do you use the disposable or the silicone?
Do you think we can order them in Lime Green Mickey Heads?
http://www.youtube.com/watch?v=jB4Fbi22hcw