RapeLay is infamous and I think having a copy; Even digital, is still illegal in some countries.
That being said, yes, is actually really good at anal only; The girls cry about doing anal, you can tease them about being virgins and anal sex has development. It has few voice lines per session, but these change over time with development. Is kinda sad to see how this game is quite old and yet has a lot of anal-only aspects.
However I must mention
PlayHome, is basically an spiritual successor and is way better just a lot more grindy (Idk if there is a mod for that), not only you can do anal-only but the game has intermission events where this is mentioned, like, one of the girls said; "I am a slut now!" and the mom says; "But honey, you are still a virgin", an actual good anal-only game (Grindy aside).
I'll be honest... I feel scammed, not only there is not enough anal, but the marketing is deceiving, like, they multiple times mentioned battlefuck where you choose the direction of the combat and you can offer body parts just like in Karryn's Prison, also, how events were tree-branch which to be fair some events and missions are tree-branched but not nearly enough, like, you have unavoidable virginity lost in multiple events when it was also mentioned in marketing that your stats will affect choices.
Idk, is disappointing, nonetheless, is a decent game, just not nearly as good as it was promised, and I am not even talking about anal-only, people is going out of the honeymoon phase and realizing how is another RPG maker hentai just slightly better than average.
Is mentioned in multiple events; The shopkeeper, the loli-yuri grooming, the bathrooms, so far I think most of the events I have seen mentions virginity but I can't vouch for this because I have unlock just those and a couple more.
What I am going to try is playing full-cheats and see if I can find a viable anal-only path, maybe by increasing the anal development early on. But in general, if you don't play with cheats for money and experience, the game isn't fun.