Not so long ago if a student of singing questioned a teacher to explain why an exercise was being done or what it was for, a teacher could easily respond, “Don’t worry about such things! Just trust me. I know what I am doing.” These days, this might not be as common as it once was, but it isn’t impossible that a student would still hear these words.
If you are studying singing and you ask an honest question and your answer from your teacher is “just trust me,” I am going to suggest that you respectfully say to your teacher, “That’s not an answer I can accept. I can’t trust you if you don’t have a clear way to explain to me what we are doing.” You will likely incur the teacher’s indignation if not outright wrath, but you should press for an answer regardless because you have a right to one that is not dismissive of your question. And, further, if you get an answer and it doesn’t make sense, go look it up in a reputable voice book or online at a medical or technical voice site to get more information. The Voice Foundation, the National Center for Voice and Speech, ASHA, and NATS all have information available on their website that can help you understand vocal production. You might be a student (of any age) but if you do not pressure your teacher to come up with accurate, useful information that can be applied to your singing, the profession will continue to get away with allowing people who have no clue to hold teaching positions, particularly at universities and conservatories. If you do not insist that you be spoken to in plain, simple English (not voice teacher jargon that needs an interpretation), you will find it difficult to learn and may be blamed for that.
There are many terms used by singing teachers that are absolutely meaningless but they are presented with such authority, such conviction, that questioning them seems like a bad idea. You may be intimated, not wanting to seem stupid, disrespectful or impatient, but words that do not make obvious, plain sense are of no use to a student. It is possible, very possible, to teach effectively without using one word that someone has made up, or embroidered with obscure meaning. Everyone knows what red is, or green, but some people don’t know what chartreuse is. If you aren’t a visual artist, you might not know either and not knowing doesn’t mean there is something wrong with you.