How to get references from teachers (volunteer application form)?

You can put anyone down as a referee as long as they are not related to you in any form. No cousins or anything like that. Yeah, they might not ever know but it is best just to do everything by this rule, even when you apply for jobs in the future. Family friends are okay, I have put down several for job applications in my lifetime. It is also okay to put down teachers as references too. However, I would not call them. Emailing should be fine but the only problem is they may not answer because it is summer. If I were you I would use family friends as your references. Hope this helps and good luck!