For those who want to know, that makes Xitter sound like halfway between Sitter and Shitter.
As an English speaker you can try to make that sound by saying the Y in YEET and paying close attention to how exactly your tongue is positioned and where in your mouth the air is being constricted. Then try to position your tongue as if you want to say “yeet” or “yes” again, but make an S sound at exactly the same constriction point where you made the Y sound before. If you’re successful, it should sound like a hybrid between S and SH to your English ears.
That’s how I make it anyway, actual Mandarin speakers might find issue with my explanation.
Might be app- or instance-dependant. I’m using Liftoff.