Honestly, I was good at hiding it. I had my moments and my blocks, but I knew what worked best for me: Stop talking, substitute words, saying other words that helps speech to flow, etc.. I'm pretty sure people know I'm a covert stutterer, but your confidence can get a really big boost if you can get thru a presentation. You know how you don't stutter when you sing? I tried to have a "flow" of my voice.. A pattern. Basically, my own song. My voice didn't change in pitch, but I had a rhythm in my head with my words. I often regurgitated the same information to different groups, so the repetition helped.