Onii-chan wa Watashi-tachi no Omocha,お兄ちゃんは私たちのおもちゃ,お兄ちゃんは、私たちのおもちゃ,Your Our is Joy Toy.
Big brother Takeya has been gone for a year. His father asks him to return home to care for his younger sisters while he and their mother are away on business. But being alone with his aggressive little sisters is too much! They want sex, they want to become his brides, they want his babies, and they won't listen to a word he says. If onii-chan doesn't want to have sex with his little sisters, they'll force him to!
It's not long before Takeya becomes their slave, their pet, their toy to play with.