I'm seriously thinking that this is the sweetest BL I have ever read so far. (Like, it's really side-to-side with Kimi ni todoke, I know they're different genders, but if you read it you'll see the similarities too). I love how the protagonists are so different yet they get along so well, as the time goes by. The mangaka did a great job, didn't miss any detail. As the story moves on, there's an explanation for every act, every tought. And the realization that maybe they're in love with each other but they just don't know how to act when they're together...they're so innocent and cute,gosh.
Of course, Sasano is the one part that in the beginning of the story already knows that he likes a boy. But for him, it's not like he is labelling himself, but realizing that, that particular boy has something that attracts him. Sasano tells himself that it's because he lives in a house full of girls, he's used to like cute things, but in reality is that Koga is just so beautiful, have a magnificent presence, that eventually he just fall for him. And in the other hand, Koga knows that he's liked, there's a lot of confession that girls make for him. Lot of boys feel uncomfortable around him, 'cause he's being annoying by just rejecting the confessions. But it's different when he's around Sasano...and he just want more of that peacefull feeling.
Please, give this manga a chance. It won't disappoint you at all, I promise.