I got to experience how it feels multiple times (being a non-stutterer, 100% fluent). How to put it into words? Feels like some invisible constipating force was removed from your being. The natural state of speaking is FLOW and absence of obstructions. Stammering is like watching an engaging youtube video that buffers every few seconds and ruins your interest in it. When I experience the state of no-stuttering it feels like stuttering is something completely alien to me, something I was never supposed to have. All the "you're brain is just wired differently" and "it's just something you have to live with" lines feels like absolute utter cope when you experience the state fluent state of freedom. This is supposed to be your birthright. Easy, natural, effortless speech.