How about I snitch on my friend?
What is making you want to snitch?
You know what? Someone stole my pencils, and it could have been you.
I have had nothing to do with that and your friend either. So no snitching can be done. Be sure you have all of the evidence first in any accusation otherwise people will see you as paranoid. You mean more to me than that in a friendship.
Nah, I'm going to snitch on you.
There is nothing to snitch about. You should really just worry about getting extra pencils.