Also his body language seems to point to the fact as well. As I said he was tired, it was extremely hot and he did say he didn't feel like dancing but we still did.
Most Helpful Girl
Sometimes there's a reflex where you are worried of invading a personal space and he may have just been startled and didn't want to be inappropriate by accident. This seems a little odd of a question coming from your age category but regardless, I think there is not a sufficient amount of information to truly tell why he moved his arm. Maybe don't over analyze his every move and just get to know him better.