Gyaru Ane Z -Gachi Kimochiii!! Atashi-tachi ga Anta no Niku Onaho ni Natte Yaru!! | ギャル姉Ｚ～ガチ気持ちイイ！！　アタシたちがアンタの肉オナホになってやる！！～

Those bitch sisters who look down on me... just you wait.

The protagonist, Niihara Daiki, has been used as a personal errand boy by his domineering sisters ever since he was little. Whenever Daiki is home, he handles all the chores. The moment he tries to protest, they start hitting him and unilaterally cast him as the bad guy. This is his daily life.

Fed up with this routine, Daiki one day hears about a hypnosis device from an upperclassman at his university. He tries it half in disbelief, but the effect is immediate - his sisters become obedient to his every command.

Hahaha, this is amazing! Those sisters of mine, doing whatever I say!

And so he begins using the hypnosis device, behaving at home as if to vent all his pent-up resentment - but...