Beautiful. Much like Reimu/Yukari and Youmu/Yuyuko, it's hard to find a sweet, mutual Eiki/Komachi doujin, especially one where Eiki is so assertive, so forthcoming.
The frankness was very admirable - it's rare to get doujins with that really comfortable, openly affectionate feeling when the pairing isn't ReiMari or MeiSaku. Yuuka was pretty nice as well.