What is the meaning of:
"I know I did," I said. I said it very fast because I wanted to stop him before he started reading that out loud. But you couldn't stop him. He was hot as a firecracker."
as hot as a firecracker.
Firecrackers are very sharp and active fireworks - so he was behaving in that way, quickly and sharply. Hot here has the connotation "excited/excitable".