When I am teaching yoga classes I often stress than we don’t really want to feel anything in our muscles while practicing, you simply want to be doing what your body is capable of doing. If your intent is to constantly go deeper and do more, than by necessity you will feel your muscles as you stretch and work them to some new limit, but that is a choice and in my mind shouldn’t be a constant. I simply want a body that works.
Every muscle has an ideal resting length and if we live in a balanced body you won’t need to “make” a muscle engage to accomplish an action it will simply do it for you. So essentially we go through the paces to build strength and stamina so that the well tuned machine takes over and the act of overworking individual muscles falls to the wayside.
If someone is particularly weak in the core I might have them engage a little as they walk to feel what proper tone can bring them but in the long run we want to have balanced toned muscles that can simply achieve their goals on their own.