If you’ve already spoken with new HBD in person I would type up an email that rehashes out any previous conversations you have held about them being aware of your after school duties, and how they had already been made aware of your personal scheduling needs outside of school. Be sure to add that you are a team player and are looking to help improve the band program but that any time scheduled beyond your after school sectionals need to be planned in advance to accommodate your family. Keep a log of how often and how long new HBD is asking you to stay past your after school sectional time. If it escalates from there involve admin.

Our contracts all have a “duties as assigned” clause but that also doesn’t mean we’re subject to being forced to stay extra late at school at a moments notice. Keep everything light and professional because something like this could make or break your work dynamic.