He's young and to his thinking that thing in your hand could be a small predator. Next time, show it to him momentarily then put it behind your back. Do this a dozen times extending how long he's able to touch it. Then wipe his forehead, cheeks, then his neck and back to allow him to touch it again. A lot of people make the mistake of going for the shoulder and his rearward eyesight is even poorer than his forward eyesight. He's not seeing it as you do. Put a little water in the sponge and wipe his face and the other parts you did with a dry sponge. When it comes to spray, first show him the bottle. Start with a bottle filled with water and spray it beside you. If he stands still, offer a small treat. Gradually bring the spray closer, aiming downward and as long as his feet stay glued to the ground offer a treat (great incentive). When the spray first touches him aim mainly for the ground in front of his hoof so just a little spray touches him and again offer a treat if he stands still. Now he's figuring out the treats come for standing still. Gradually work up to his knees, no higher, then to the shoulder and along his back and sides. Go back and offer a treat for standing still. You could likely finish him completely at this point. Leave the neck and chest for now as he'll be concerned about his ears. After you've repeated the spraying and rewarding for three or four days he should be ok about the neck and chest. I have one that I did this while he was at liberty and could walk off. When he did so he realized no treat. It was comical watching him sort this out. I waited and he came back and got his treat and I was able to spray him all over. As long as he's allowed to touch the bottle first he's giving me the ok, even when loose in the pasture. He was long ago weaned off the treats altho he may still get one for standing still when I'm done spraying but only sometimes.