Mazomai ~M na Imouto no Ecchi na Onedari~

The protagonist, Kusuno Takumi, lost his parents 10 years ago and has been raising his three younger sisters on his own. He and his siblings live a modest life together, running the coffee shop that his parents left to him. One day, while cleaning his parents' room, whose hobby was collecting antiques, he finds a milk pot with a cute fairy painted on it. He thinks it's something suspicious, since his father likes the occult, but his sisters seem to like it and immediately start preparing milk tea. Then, something strange happens to the sisters who drink the milk tea. They suddenly approach the protagonist and start begging him to do naughty things. And it's not just naughty, they ask him to bully them. The protagonist is confused because he can't bully his precious sisters. But the sisters ask their beloved brother to bully them. Then the erotic and silly daily life of the brother who can't bully his precious sisters and the sisters who want their brother to bully them begins! ! [Translated from DLsite]