Going temporarily mute can be a really weird experience, and is something I imagine is very personal to the individual. When it happens to me, I usually end up wanting to be wrapped up in a blanket or thick hoodie in the dark in a soft, quiet place like my bed. Sometimes I'll stim with a toy or something, and sometimes I'll just kind of dissociate until I have the energy to speak again. If you haven't already heard of it, Stim Punks Foundation has some amazing content: (this links to their situational mutism page). Here's a great graphic from them that might help too. It's cut off but the full thing is on that page I linked and includes sources with further reading.