This is one of my favorites of all time. It's AlphaxAlpha, VERY steamy, but can still maintain a nice and non-toxic dynamic between the two characters. It originated from a novel, and that very much shines through.
You may feel your favorite manga should be gathered together into distinct categories for your own reference and, now, you can do this with a LIST. After you've created your list or lists, you can proudly recommend them to other manga fans to showcase and share your taste in manga.
Norainu no Yoru