Otose... Iyagaru Ano Ko o Biyaku de Otose!

Shibutada likes games, anime, and, of course, ero games.... Yes, he is a perfect otaku. One day, he receives a wrongly delivered package. But Sawa, his younger sister, opens it and eats chocolate inside the package.... A while later, her attitude gradually changes.... It seems the chocolate she ate is a love drug....