Desensitization is one of the most important aspects of therapy for school-age children. A key to success in my opinion is to build a strong foundation before beginning the process: ensure that the child understands about the speaking mechanism, how he uses his speech mechanism to speak, what he does with this speech mechanism during both fluent and stuttered speech, and what stuttering is (in age-appropriate ways, of course). This foundation helps to demystify the process of speaking so that he is ready to embark on the desensitization process. This also helps to empower him because it reduced the sensation that he doesn't have control over his speech.
Then, I go into a discussion of non-speech aspects of desensitization. Typically, I start by discussing something that people fear (often, it's bugs—I used to have a very strong fear of spiders) and we talk about how we might overcome a fear. Kids often start by recommending avoidance strategies (kill the bugs, run from the bugs, etc.), but they rapidly come to see that this doesn't eliminate the fear, just the situation.
Ultimately, they learn that the best way to overcome a fear is to face it.
When we bring that into stuttering, then they see that they have to stutter in order to overcome their fear of stuttering. We have a lot of fun talking about how crazy that sounds.
After that, we can start to explore what it means to stutter, and I introduce pseudostuttering. It's a very powerful technique for experiencing the moment of stuttering without the typical fear and loss of control that accompanies true stuttering.
We start out by getting comfortable with pseudostuttering in the therapy room—again, lots of fun games can be associated with this. Then, we work to build a hierarchy of situations where we can take this new skill of stuttering without fear into the real world.
The key to the hierarchy is to go step-by-step—make sure that you don't move too fast because that can be scary. There are a ton of activities that can be done with this. Ultimately, though, kids learn that they can stutter anywhere, anytime without fear. THAT is the key to desensitization.
There is a ton more I could say about it—it's all described in School-Age Stuttering Therapy: A Practical Guide. We also have a free practical tip handout about generalization available on the Free Resources section of our website.