What should private lessons be like? The voice lesson environment should be:
Worthy of the investment of each party's time
What should private lessons not be like?
An emotional burden
Never sexual touching or any touching without permission
Those last few are jarring, aren't they? I hope you are asking, is that really a thing? But then you are probably say, "yeah, :-("
A vulnerable child, teen, college student, or adult might become the victim of a sexual predator in a voice studio. It seems to be rare. In the professional organization of the National Association of Teachers of Singing, which has a strong and honorable Code of Ethics and active Ethics Committee, the topic of abuse is discussed by the National Board on a regular basis. They ask “Has any abuse happened that we know of?" and “What can we do to make sure it never does?" Colleges and music schools are also aware of this evil possibility and train their teachers about prevention.
What can a student do to ensure this never happens to them in the voice lesson environment? The easiest thing is to record every lesson on a smartphone. The mere presence of a recording device will be a substantial deterrent. Recording lessons is common practice with the bonus that listening to the recording, even once, can accelerate learning dramatically. It also gives evidence in case of a transgression.
There is a flipside to this coin however. The teachers are also victims of unwanted advances. In my experience sexual advances toward teachers happen at a much higher rate than toward students. I don't know a single teacher who has sexually abused a student, but I know one male teacher who had a student offer an exchange of "pleasure" for lessons. He declined, laughed at the suggestion, and taught her how to sing anyhow. Another male teacher told me that a new female student took her shirt off during the lesson, her idea, just in case he "wanted to see her breathing better." He left the room until she put her shirt back on and discussed the situation with his department chair. I've had two adult male students make advances toward me. One took my clear rejection and remained an excellent student. The other left my studio.
This happens. And we must take preventative measures. Be smart. Record lessons. If the person you are with makes you at all uncomfortable discuss it with the person. If that doesn’t go well, talk to their supervisor or organizational representative, and take steps to not be alone together. Don't let a creep ruin your music!