This is one of my most favorite yaoi. (i've read a fair bit and i'm really picky especially when it comes to this genre, so.. that means its pretty darn awesome)
Firstly, I love the character designs. I have always liked Kyuugou's drawing style. The characters look more 'real', they have this sense of boyishness and masculinity that is totally absent in some yaoi/shounen ai mangas. But of all the character designs out of all her (i think its a her?) manga, the two main characters here are probably the best ones. They're quite unique (and very cute hehe)
And the story. Its a one shot, so chances are you wouldn't expect much. But this one had a surprising amount of depth and i'll just say it's not tagged as psychological in mangafox for nothing. Everytime i re-read it i'm amazed with the author for crafting such a story.