It is important to teach children about emotions. One of the most important things for them to know is that emotions affect our physical body.
Principle: Emotions lodge in the body.
This is a simply poster that I made up for our family. You can easily do the same thing. Post it on your frig, and talk periodically about it. Questions such as these can be simple, but meaningful. "What does your mouth do when you are angry?" Child might say that it could yell, or that it could scream. You could point out that we could also "hum a favorite hymn" to calm down, or we could remember to "keep our mouth closed until we have time to think."
Ask: "When you feel frightened, what does it feel like in your heart?" That could be an interesting discussion too.
Do a lot of role playing with your children. Role playing is important, because it allows you to pre-teach your children and help them figure out possible situations and what they might do if they encounter something similar.
The point you really want to emphasize is that emotions do lodge in our bodies. When we know this, it is easy to see that we can help ourselves out emotionally if we will use our body to process those emotions.
Also - children do not readily recognize emotions. Understanding that there is a body connection will allow them to realize that they are feeling something. This will give them an opportunity to think about what they are feeling, and analyze it.
That's the goal. We DO feel emotions. Emotions are actually a good thing. The thing we need to do, though, is to recognize our feelings and thoughts, and to process them consciously, rather than letting them take control of us because we are not aware.