心海在摸鱼时被爷当场抓获，于是请爷吃寿司想让爷保密，但是为什么要脸红？

心海はサボっている時に俺と出くわした、そこで俺に寿司を奢る代わりに秘密にして欲しいと言った、しかしなぜ頬を赤らめる？

I've caught Kokomi red-handed while she was slacking off, so she served me some sushi so that I would keep the secret to myself. Though, why is she blushing?