A music "demerit" for the elementary general music teacher.
If a student is not acting appropriately in music class, give them one of the small sad note cut outs and have them sit out of the activity you are currently doing. If their behavior improves, you can take the sad note back.
If the student's behavior does not improve, exchange the sad note picture for the sad note form, which has to be signed by parents.
It has worked well in my classroom! :)