![](https://pic1.mangapicgallery.com/r/avatar/90/u115862_50x50.jpg?2)
I think Kurose doesn't want to tell his story with Nishigaki to Shirotani because he thinks that Shirotani will be hurt if he will come to know about. Kurose also thinks that Shirotani will come to hate him because Shirotani will assume that KUrose only helps him because of NIshigaki and that Kurose doesn't really love him.
I wonder what did Sensei mean when he said 25 points to Masahiro. Heehee~ (づ ̄ ³ ̄)づ
btw, this is what im referring to. http://www.mangago.me/read-manga/hitorijime_boyfriend/uu/hitorijime-boyfriend-chapter-6.html/pg-8/