My stutter flares up when I'm anxious. This actually includes when I get overly caffeinated. Deep steady breathing exercises and meditation: I envision a dolphin diving down into the ocean as I breath in for 5 seconds, as I exhale for 5 seconds I envision the dolphin rising through the waters and bursting through the surface of the water. I repeat this for as long as I'm able. I try to remember this nightly, as a practice, as I'm falling asleep. With this rhythmic breathing, I will throw in muscle tension exercises. Starting with my toes I tense them up as tight as I can and then hold my breath for 10 seconds. Releasing the breath and the muscle tension at the same time. I work from my toes, through my legs, glutes, torso, arms, neck, mouth and eyes... repeating the procedure. With each muscle group, I try to focus on the feeling of relief I get from the relaxation of the muscles and the release of the breath. I practiced this to the point that often times, I can simply envision that dolphin in my head and I can feel some of the tension release, even without the breathing or muscle exercises. I think you could consider it a form of hypnosis. Through the meditations and exercises, I'm repeating suggestions to myself to relax and associating it with a vision. This, unequivocally, has been my savior. I'm 40 now and for the past 20 years, I've used this tactic to relieve my tension and thus drastically reduce my stutter. I know different things work for different people (despite what Steve Harvey suggests), but I'd certainly recommend giving it a shot if you haven't. Spotify has a series of relaxation/trance inducing stations you can listen to that may be good as well to go along with the exercises.