The first Futaba Channel game was officially made free. If you visit the gallery you'll find it on a link to the company's homepage. (I don't want to post a direct link, but I know you all have e-hentai accounts.)

https://exhentai.org/g/70584/321b9e0790/

It's not that great of a game, and unfortunately the sequels have basically fallen off the internet, banished to dead link hell. There's a masturbation scene, and then a lot of rape. It's really long though.