I have that issue myself. What i do is tell I have a speech issue/impediment etc and then proceed with the topic at hand. Something I do went I get stuck is, when I talk to people like you described I point at my mouth while I get a block and if they have half a brain cell they figure out I got some type of issue 😂 Also I'm in college , and I have to do a video presentation soon. So I let my instructor know about it and she understood. Don't be afraid to let people know or ask for help. Our stutter is nothing to be embarrassed about. Everyone has issues, it just that our issue that is out in the open.