The ‘lip roll’ is often used for vocal training. A lip roll is the term used for making the lips vibrate through exhalation.
The lip roll is made by using the orbicularis oris muscle. The orbicularis oris muscle is very important due to its role in closing your mouth and is considered complex.
If you strain the orbicularis oris muscle too much, you will not be able to vibrate your lips sufficiently. Conversely, if you ease the orbicularis oris muscle too much, when you open your mouth widely, you will not be able to let out your breath properly.
People who can do a lip roll really well, usually strain the orbicularis oris muscle at first on purpose and then ease the muscle later.
Additionally, if you do not exhale when doing a lip roll with a steady speed, your lips will stop vibrating. This is also a good technique to practice for breathing training.
If the lips are too narrow or if there is too much of a space when forming the lip roll shape, it will be difficult to produce a good sound. Keep in mind this tip, you definitely cannot touch your teeth to the inside of your lips when attempting to create a lip roll. Touching your teeth to the lips will only result in muffling and ceasing the lips’ ability to vibrate.
If you stretch your orbicularis oris muscle with your fingers before doing a lip roll, it will be easier to do the lip roll for a longer period of time.
Red is the part of the orbicularis oris muscle.
Note: A vocal coach once asked me, “Some of my students cannot do the lip roll, even if I teach them the simplest basic techniques. If they keep practicing and training, will they be able to do the lip roll someday? Or, is it just physically impossible for some people?”
My answer to him was: We have still not figured out the exact mechanics regarding variations of the tongue and orbicularis oris muscle, because it varies greatly from individual to individual. Therefore, it is very possible that an individual may not be able not do a lip roll physically, even if they practice and do a lot of training.
If you do not have this problem, you can do lip roll when you train by moving the larynx and suprahyoid muscles.
But please be aware that some people cannot do a lip roll congenially and if you force them to do lip roll and they constantly fail, they may not favor singing or vocalizing. So, be patient and positive when training or assisting others.