We just got back from our first trip to WDW. (had a great time 
This is what we did. We got a pet tag (just a round one) that had our last name, our resort and our cell phone numbers. We also bought him a whistle on a necklace. we put the tag and whistle on the necklace. He wore it with no problem at all. (Plus, he liked to blow the whistle, but only when he asked.) He understood the the whistle was ONLY if he looked around and couldnt find us. He was to blow the whistle, if we didnt come in a few seconds he was to go into a store and find someone who was wearing a WDW tag. We pointed those out different places all through WDW so he would know. It worked great and luckily, we never had to put any of it in practice. Have a great trip.
Kris

This is what we did. We got a pet tag (just a round one) that had our last name, our resort and our cell phone numbers. We also bought him a whistle on a necklace. we put the tag and whistle on the necklace. He wore it with no problem at all. (Plus, he liked to blow the whistle, but only when he asked.) He understood the the whistle was ONLY if he looked around and couldnt find us. He was to blow the whistle, if we didnt come in a few seconds he was to go into a store and find someone who was wearing a WDW tag. We pointed those out different places all through WDW so he would know. It worked great and luckily, we never had to put any of it in practice. Have a great trip.
Kris