right now when you mask a game it completely vanishes from your activity, but also from your library. This is very useful for games that you don't play anymore, or for some reason you judge obsolete. But it's not handy for adult/sex games. each time you want to launch an sex game you need to search for it in the research bar, or go to the options and click show masked. this is not really handy
what i suggest is the ability to tag the masked games so we can see them in the library. the idea is to keep those game activity masked, but still keep them at hand reach for an easy launch