To those who have gone down the stuttering severity level.

To those who have gone down the stuttering severity level. Has anyone managed to go down the stuttering severity level i.e from Severe to Mild/Moderate or from Mild to Slight How did you do it any tips, Like today I was speaking to my nephew his father asks me to explain to him newtowns third law(Every action has a equal reaction) As soon as he said the words "Can you " my heart rate jumped , and I started stuttering (blocking) How do I reduce / eliminate this tension? Really don't understand how guys such as Michael Sheehan, John Tossel have become successful even though they have a stutter