How Did Dad End Up Selling Me to a Beautiful Girl?

Tsundere Heiress: "Y-Yeah, Xiaoran! You still have a long, long way to go!"

Adorable Little Sister: "You worked hard today, big brother. Want your little sister to give you a massage?~"

Bossy Little Sister: "Hey~ Big brother, don't go flirting with other girls while I'm away!"

Waaah, this is a school romance about an adorable boy surrounded on all sides by a group of young ladies.