First an observation - I noticed that I can not inflate my cheeks with my mouth open. This means that inflating cheeks is not a muscle property and that only pressure of air from lungs trapped inside my closed mouth is responsible for any inflation. Also, once inflated I can move my tongue anywhere and still retain the inflation. This means that tongue is also not responsible for air regulation inside mouth.
Moving on, we all know that we can either inflate both our cheeks, or we can inflate only cheek from one side or we can inflate *portion of face between lips and chin* (I don't know what it is actually called). Put simply, we have complete control over which part of my face would I like to inflate.
I don't understand how this is possible without muscle control? Air has tendency to occupy all space therefore my entire cheeks should get inflated without me having any control whatsoever, but as it turns out I can control and redirect the air to apply pressure only at a particular cheek without any help from tongue. How?