One of the fundamentals of singing is to understand that in the process of learning and growing, we will make mistakes, and that is okay.
The vocal studio should be a safe place to explore all the different vocal sounds. The teacher acts as a guide, and the student is encouraged to respond to the musical exercise without fear of messing up.
The vocal exercise will be constructed, including with a type of rhythmic feel, to assist the student. The exercise will stimulate the vocal muscles so that they respond with reflexive activity, like when the doctor taps the knee with the little hammer and the leg flies up due to a reflex action.
Basically, the voice responds to the exercise automatically; producing sensations that might be completely new for the student, previously unimagined. Once this new experience has occurred and is repeated, then the mind and the body remembers this thought-hearing feel and voila!
However, one cannot get to voila if one never tries. So sing the exercise without worry, and pay attention to what happens. We are almost always pleasantly surprised.