Masking is just acting in a way that you normally wouldn't, but have to. Think of a spy blending in avoiding to get caught, it's a conscious effort not to screw up and it takes more energy/willpower from you than not having to pretend to be someone else. I guess it gets harder the more different from yourself you have to act, like having an itch you can't scratch or will get "punished" somehow, damn.

Even just learning that there’s a word for this has kinda opened my eyes