I’ve heard it compared to a sneeze or cough like they feel it and know it’s coming so they fight the urge for a bit longer until it’s uncontrollable and the coughing fit comes, worse than what it would’ve been if they coughed the first time For me, it depends on the type of stutter but they all involve uncontrollable movements or lack of movements. Like with a block, I’ll just freeze up and be unable to move my mouth like I want to. Repetitions do feel a bit compulsive though especially the tics I’ll get(rapid blinking and twitching). I can also feel and expect a repetition I’m about a to have There’s definitely differences between the two but they sound similar in a lot of ways too. There aren’t many studies on stuttering so no one really knows what happens but I remember reading that it was an “involuntary, uncontrollable movements of the vocal cord and other muscles related to speech” or something like that