My Sister's Friend is a Beautiful Senior Who is a Year Older, Spoils Me to Death.

Hina Airi, a senior one year above me, is renowned as the most beautiful girl in school. To me, Masahi Shuuma, she’s just my sister’s friend—someone I barely know beyond a polite nod… or at least, that’s how it was supposed to be. "Looks like I enjoy spoiling you, Shuu-kun." It all started when I visited her house to check on her while she was sick. Since then, Hina-senpai has been closing the distance fast—homemade meals, dates, lap pillows… "Hey, I want you to teach me more. Why does my body ache for you—?" She shows me a side of herself no one else gets to see. Before I know it, we’re in a temporary relationship!? "I’ll make sure you can’t live without me, so you’d better brace yourself." A romcom where my senpai pampers me into blissful ruin! (Source: Kadokawa, translated)