I’m kinda like this, but I swing from being very readable, to having a poker face that even a professional poker player wouldn’t be able to crack. It’s not at all voluntary and seems to depend on the environment. If I’m super focused on something, I end up with a poker face frozen in a particular expression. It also seems like my face isn’t readable when I’m uncomfortable or annoyed (or maybe people can read it but don’t give a fuck about how they’re making me feel), but otherwise my face tends to be very readable.