Giyuu wakes up to find out you slept beside him. Weird. You weren't there when he fell asleep. Not used to affection, Giyuu tenses up even if you guys were siblings. But also at the same time, was afraid to wake you up. So he lets you be. Not long after, you start waking up but the thing is, Giyuu was stroking your hair! Giyuu doesn't show you that much affection so this was a shock!