Ah, dang. Every time I see "Yakyuken" I think it's an old game I used to have, a long time ago, but it never is. I think the title of it was also "Yakuyuken" but I don't really remember.
It was in Japanese so I have no idea what was going on or what the "plot" was (little as it was) but from what I could gather, some woman spills a drink, and is forced by a man (the owner of the establishment she's in, maybe?) to play strip rock, paper scissors. Two guys are sitting in the background watching. Eventually, if you strip all your clothes. you have to service the man in various ways, and the two guys in the background also join in, eventually leading up to sex. I also could be remembering things a little wrong, but that was the gist. It wasn't animated or anything.
I somehow lost the game and have never been able to find it since. I always get my hopes up when I see "yakuyuken" on any forum. It's been a long time. Oh well.
This game, though, is also pretty fun, if for no other reason than to pass some time.
It's back again for version 4.07u, along with two new characters.