I believe that this question is asking about a sequence that happens in chapter 12. This is when readers first meet Mrs. Donelli, and we are told that she is the English teacher and new to the school. Max makes sure to mention her being new and uses it to explain why she doesn't know that asking Max to stand up in front of the class is pointless.
Mrs. Donelli is taking attendance, and she asks each student to say something about their summer. Max is definitely not willing to do that, and all of his classmates know it. Unfortunately, Max's classmates aren't supportive of his hesitancy to be the center of attention. His classmates take this situation as an opportunity to make fun of Max:
"Forget it, Mrs. Donelli, his brain is in his tail!"
"Ask him to count, he can paw the ground!"
"Maxi Pad! Maxi Pad! Ask him quick about his dad!"
"Killer Kane! Killer Kane! Had a kid who got no brain!"
It's clear that Max's peers have a very low opinion of him and zero respect for him, his situation, and his past. Max doesn't even try to defend himself, and that tells readers that Max's opinion of himself is so low that it isn't even worth trying to defend his own honor.
It is Kevin that comes to Max's defense. He directs the class's attention on himself and explains that sometimes he is Kevin and sometime he is greater than Kevin because of Max. Together they are "Freak the Mighty." The class loves it and starts chanting in support. Max embraces the situation and feels like he and Kevin can conquer anything together.
I’m standing right there with Freak high above me and it feels right, it makes me feel strong and smart.