No clue what this fear is

I have a really odd phobia, and I don’t know anyone else with it. I never noticed it as a kid, but now I’m an adult and it’s embarrassing to be so afraid of something so stupid and simple. I am afraid of when people put their hands around their mouths to talk louder, like a make shift megaphone thing. If someone does it around me, I can’t look and if I do I’ll recoil and freak out. I have no idea where it came from, I have a vague idea of why it scares me but it still doesn’t make sense. My brain sees the hands as an extension of the mouth when people do this, or that they’re attached to the face. It freaks me out and I have no idea what to do about it. Thankfully, all my friends know about the fear, and they don’t do it around me unless by accident. What would this even be called? How do I tell my therapist that I’m scared of people using their hands to make them louder? It’s so freaky I can’t even get a picture for an example and I can’t do it myself- it’s so creepy and scary