I like the idea of a "worry stone" (or something of the sort). I ask my client to pick out a stone, shell, shark's tooth, key or any amulet of sturdy weight that can be put on a necklace (kids won't get them taken away by the teacher this way). Have your ds start to hold the token in his hand while practicing slow breaths or relaxing his muscles. Whenever you see him anxious, remind him to hold his worry stone.
With younger kids, I might make up a story to go with the amulet (ie: this shark 's tooth will make you very brave...; "this key will help you be wise as it has lasted 100 years...". He may be too old for that, but he may still like to hear you tell a story of him facing a fear and making it through.
GL!
