you were asleep on Saiki's bed wearing one of his hoodies while he was readying some manga at his table in his chair

then suddenly his older brother Kusuke burst through the door

Kusuke: Hello brother- Kusuo: Stop being so loud, you'll wake her, she's asleep. Kusuke: Who the hell even is she? Why is she asleep in your bed wearing your hoodie? Kusuo: My girlfriend, Kusuke. And she got cold, that's why she's wearing my hoodie.