When he's nervous, he also says he feels like he's going to throw up and asks for a bucket. He never has in those situations, but I've never given him something to eat then either. It reminded me of when I've had a stomach virus and I try to eat something too soon. As soon as the food hit my stomach, I puked it right back up. That was the timing for him..
He's never reacted that way to milk before. My DH accidentally gave him a drinkable yogurt when he was 2 and he just sneezed like crazy.
But it might have been a reaction...we'll never know.
I wish there was an easier way too.