Hi there, it's always so wonderful to hear from parents who are tapping with their children!
One of the things I encourage parents to do is to make tapping part of the "tucking in" ritual. Talk about "the worst" thing that happened each day and tap away any remaining negative charge, then talk about the best things that happened and tap in those good feelings.
Another thing I like to teach the children is that they can identify and then become aware of the physical sensations in their bodies that "alert" them that are becoming angry or sad. We start off by asking where they start to feel angry, for example -- for some children, it's the stomach, for others the head. Next, I ask them what the feeling is like -- some children start to feel to feel a heat rising up, or they feel agitation or clenching in their stomachs. Different children will feel different things, so it is important to help them learn their own language. Once they recognize the signs, they can ask themselves why they are starting to feel angry...possibly because someone hurt their feelings, was disrespectful to them, or criticized their work making them feel dumb or stupid. Then of course, they can start tapping. Some younger children may have difficulty understanding or articulating the "why's" so I tell them if they don't know the why, just start tapping anyway on this "angry" or "sad" feeling.
Schools are definitely becoming more open to the use of EFT. I just recently was able to present a workshop on EFT at the Texas Counseling Association Elementary Counselors Conference, and had a marvelous turnout and response. Counselors are looking for something that works, because their hearts are to help children.
You might find further ideas on the Teacher part of this forum as well. Your son is fortunate that are giving him such an empowering tool!