You made a mistake in classroom. Write a letter to your teacher. In the letter: state your apology; describe the situation; write about your promise to change.

Dear Mr Garjani, I am writing to apology for my inappropriate behaviour in the classroom yesterday, which led to your dissatisfaction. I am really sorry. I did not like to make the classroom crowded, and I just want to have some fun. However, my mistake gave rise to students who were distracted with my action. […]