Didn't they add the option to make games private because people made this complaint? The issue now is on family accounts and not seeing it, because there you still can. I don't need to know what my family is into, thank you very much.
Right click a game (or press Start in BigPicture/GamingMode), select Properties. Go to the Privacy tab, and there you can hide the game from everywhere but yourself. The game will only be visible in your own library when logged in, and people won't see you playing that game when you run it (you appear Online but not playing anything, your nickname in friends list remains blue). You also make the game invisible in your profile, both on the main page with the play time and on the full games list.
You can also do it before purchase, now every time you put a game in the cart you are asked if you wanna make it remain public or hide it.
Away from pc but from what I remember when you go into the friends window, after clicking the friends button in the bottom right, at the top of the new window there should be an arrow. From the drop down you should see active, away, invisible, and offline. Choose invisible to be able to see your freinds, talk to them, etc. but show up as offline for them.
Whenever I'm online I get alot 9f requests to play comp on cs2 so it's helpful when I just want a calm stardew valley evening, or I'm already 5 stacked. It's not just for porn. I have no idea why you'de buy porn off steam though. That's a wild idea
The only hentai game I played through to the end was Hunie Pop.
Nearing the end I got an alien artifact, and showed it to Nikki, the geek girl who was a UFO and alien-life enthusiast.
Look, Nikki, actual material evidence of extraterrestrial intelligent life. YOU WERE RIGHT ALL ALONG! Sadly, Nikki gave me the canned ERR: Not on my designated list of acceptable gifts response. Disappointed.