Can't use mask painting in Clip Studio Paint!?

Over the three-day weekend, I was trying out various painting procedures in Clip Studio Paint.There are countless ways to ...

[Creating Uni's LINE Stickers] A story about how trying to animate LINE sticker images turned out to be way more of a hassle than I thought!

I tried animating this in Clip Studio Paint, sticking to the basics. I know how to do it. I know how, but... it's such a pain ...