I would begin your presentations by telling you’re audience that you stutter. Maybe even make a little joke about it. I used to say something like “Ok guys I stutter so talking in front of groups is really challenging for me but I’m going to give it my best. If I get stuck or look like I’m in pain don’t worry I’m fine. I’ll try not to keep you here all night haha.” It will put you at ease but will also put the audience at ease too. Most people don’t know much about stuttering so when it happens they’re not always sure what’s going on or how to react. By telling them up front they know what to expect and it frees you from the burden of being fluent or hiding your stuttering. Everyone is on the same page. Fluent speakers freak out about presentations too and you will be an inspiration to them. Try and have fun up there. I know that sounds weird but I really mean it. Stuttering does not equal failure. Avoidance is failure. Quitting is failure. Tackle these presentations head on. Show these sons of bitches what you’re made of. One last tip. Don’t address the audience as a whole, it can feel overwhelming. Pick individual people out of the crowd and talk directly to them. Especially people you know. I guarantee they will smile at you and encourage you. You can do this.