Theory:

     "Let us thrash him first and then throw him against the wall as he threw me!" this was the Master Notebook, his voice shrill with fury.
 
     "No! No! Let us all bite him and let him see how it feels to be chewed!" This obviously was Mr. Pencil Box.
 
     He became so agitated that he once again opened himself and spilled some more pencil shavings on the floor!
 
     "I suggest dragging him around the courtroom a dozen times will be a good punishment," said Mr. School Bag.
Explanation:
 
Firstly, Master Notebook proceeded to speak out angrily in a loud voice. He suggested to hit Mahesh severely and to throw him against the wall.

Mr. Pencil Box demanded to chew Mahesh as he chewed him, to make him feel or understand being chewed. Mr. Pencil Box angrily shouted and became so excited that once again, the Pencil Box got himself opened. It made him to spill some more pencil shavings on the floor.

Mr. School Bag gave the next suggestion. He suggested to drag Mahesh a dozen times around the courtroom as he too wanted to punish him in the same way he had suffered.
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
Thrash
To hit someone as a punishment
2.
Shrill
A loud, unpleasant voice
3.
Fury
A strong anger feeling which lasts for a minimum period
4.
Agitate
To make someone feel strongly about something
5.
SpillFlow or fall out of something and become lost
Reference:
State Council of Educational Research and Training (2019). Term-3 English Standard-6. BROUGHT TO BOOK: Madhumita Gupta (pp. 109-112). Published by the Tamil Nadu Textbook and Educational Services Corporation.