Mmmh I guess you didn't watch the anime? Because Kisa is a Twink who has no experience with long term thus is awkward when it comes to display affection. Or you can read the manga if you don't want to watch the anime. Both the anine and manga are called: Sekai Ichi Hatsukoi
It was really good but the uke's personality did not match his appearance. I love it no less but I wasn't ready for that at all..