Getting the little kids to listen to you?

I am a brown belt in karate, iam 16 years old. I am often asked to teach the lower belts aged 5-11, they are terrors, they don't listen and they run around screaming, which looks bad on me. The teacher won't let me give them pushups. I have tried bribing them , it doesn't work. They have 5-10 minutes beffore cl to act like little hooligans. I hide before cl because they are so crazy, my rule is unless they are fighting or going to hurt themselves stay out of the gym! Please help