I encourage the students to compose and alter pieces, so long as they are aware of the composer's intentions. The idea is for the student to collaborate with the music. Pop music is often collaborative and creative. Classical music can be forbidding. Masters in any field make you want to follow.
Any good teacher needs a certain amount of theater.
I try to bring some drama to the lesson, which allows energy to continue rather than short-circuit. As in the theater where each audience is different, each student is different. I use a three-ring binder and have a binding machine so that I can put together all the pieces a student likes. Each student is on his own for 6 days, so I help them work out strategies that work for them. Often this is through trial and error.