I want to answer some questions which some of you've asked me.
You want to play this game or another adult game but you don't want your friends to see. So here you can find some tips:
Delete from your library:
https://www.theverge.com/2015/12/4/9848930/steam-library-delete-games-permanently-how-to
Hide what you are currently playing (various alternatives):
https://gaming.stackexchange.com/questions/94211/is-there-any-way-to-hide-your-steam-status-from-others
Hope these helps!