Playing team defense is always hard. Why? Because trying to get six guys to work together to stop the other team isn't easy. The one thing that must be stressed is communication.
Communication is what is going to make or break the team defense.
The first thing you want to do is decide if you are going to play man defense, zone defense or both. If you don't know which one, then you need to play man defense. It is easier to teach.
Man Defense
Simply broke down each guy on your defense guards a guy on the other team. So, what is so hard about that? Well, as the ball moves around the field and kids watch it, they forget who they are guarding.
Players need to know where the ball and their man are at all times. Now, if your guys can guard their man and never get beat you are done coaching. But, that won't happen--you need to have a plan when your guys get beat. This is called a slide package.
There are two basic ones: a crease slide (guy in the crease slides to the ball to stop him) and an adjacent slide (guy closest to the ball slides to the ball to stop him). Once you decide which is best for your team, you have to practice it a lot.
If you chose the crease slide package, then when your crease guy slides the guy that got burnt has to slide to the crease defender so he isn't open. What makes this defense hard is teams that attack fast and repeatedly can confuse the defense. But, that is what practice is for. That is why communication is so important. If everyone on defense understands what is going on at the same time, then mistakes are cut down.
The goalie is the key person to the defense and the communication process. The goalie has to let everyone know the same information at once. That is why your goalie has to be loud and smart.
Kids will make mistakes, but learning from them is far more valuable. Understanding why they got beat for a goal can be a good thing if it doesn't happen again.
Zone Defense
Next we have zone defense. This is a little harder to play but can be very effective if played right. You can set it up in many different ways, such as a 3-3 or a 2-2-2. But no matter what way you set it up, you have rules for the kids so they will know what they are doing.
These rules are simple. For example, play this area and when someone comes in you try to force them out. Or, if the ball is on the other side of the field then you slide towards the goal for backside help. But again, the communication has to be there to be effective. That is the most important thing in good team defense.
Many kids start playing lacrosse for two reasons: to shoot and score or to hit people. The kids that want to hit people like to use the six-foot pole as a sword and that isn't what it is made for. I tell my guys all the time, let the other team make mistakes and limit yours. If you have good body position and good hand checks at the right time that is what good defense is about.
Offensive players want to shoot now and tend to force shots after a while. That is why if you guard your man with great body position and a good hand check then you will be doing your part for the team to succeed. But, like always you players have to have a passion for what they are doing if they want to have a great defense.