Really loved this one! Such an unique set-up: For starters, the uke actually wants sex! Admittedly, he does change his mind after he realises his mistake and that does lead to a bit of non-con, but as the story progresses it's clear that he does still want and enjoy the sex. I should also point out that the smut is hot, so that was another bonus.
Also despite all the cruel things Ryuuichi does, Yamashita is actually also pretty cruel to him right from the start, if you look at it from Ryuuichi's perspective (he points this out himself in ch 4), so I just can't hate Ryuuichi at all. Yeah he does some mean things, but he's also feeling used and instead of getting upset about it, he gets angry and becomes a bit sadistic.
Anyway, if you're thinking the same things as FrostyNoire, then I advise you read all 4 chapters plus the extras, as I think they show that Ryuuichi isn't as bad as he seems. He actually becomes pretty sweet in the last chapter when he's finally honest with Yamashita, and in the extra called "One Random Day" he does get his comeuppance lol.
So don't let warnings of rape or victim-blaming put you off this, it really isn't as bad as it sounds. It's got a funny and unique plot, with pretty deep characters and gorgeous art. Yamashita is a naive kind of guy, but he isn't at all irritating. In fact when you think of the trauma he experienced when he was in school, it becomes completely understandable why he acts the way he does. And as for Ryuuichi, he just gets plain jealous of his lookalike most of the time lol.
So I was going to give this 9.5/10, but thanks to the wonderful extras, I'm giving it top marks instead ^__^