A few weeks ago, we were at a restaurant. He ordered Lemonade on his communication device (CD). (Even though I suspected he really didn't WANT lemonade and wanted coke, I wanted to respect his choice.) After eating and barely drinking the lemonade he was clearly waiting for the waitress to bring him a coke. I asked him what he wanted (via CD) and he pressed Coke. I told him that he ordered Lemonade and that when he orders something, he has to go with it--he didn't have money to get another drink. I KNEW that this was risky, because he could've had a full meltdown and the place was packed.
He stood by our seat while I went to pay and I kept an eye on him, praying he would continue to be calm. When I finished paying, I gave him his coat. He hung it back up. I gave it to him again. He hung it back up. I explained that it was time to go and that we could get Coke at home. He put on his coat and took a few minutes to get out of the door. All during this time he was quiet (normally there would've been SOME vocalizations.)
Once we got out the door, I breathed in a HUGE sigh of relief and told him that I was SO proud of him and gave him a high five and a hug. As we walked towards my car, he would stop and look back at the restaurant as if deciding whether he was going to go back in and get a coke. I kept telling him how mature he was and how proud I was of him. He got to the car and got strapped in and realized what he had done and he became proud of himself. He was so excited and proud. It was a HUGE moment. I got very teary-eyed when recounting it to his parents because very few other people would understand what a GREAT success that was.