I've always been a little uncomfortable with Karen-chan, the big-breasted older sister next door, because she's always been unfriendly and cold. but our parents are close, and my parents decided to have her take care of me for a week while they're on a trip! despite her brusque attitude, she somehow teases me! she watches my av without permission, calls me to the sm club where i work... and then i suddenly realize. big sister, does she actually... ? a cohabitation life where i'm teased by a tsundere big-breasted older sister, experienced entirely from my subjective point of view!