出るに出られないクローゼットから、決して見てはイケナイ弟のオナニーを見てしまった姉はコッソリ発情！真面目で純粋だと思っていた弟の部屋にはオナニーグッズがいっぱい隠されていた。それを発見してしまった姉。でもその直後弟が帰ってきた！

My younger brother, who I thought was quiet, turned out to be a masturbation maniac who squirts many times a day! When I was surprised to find erotic books and AV in my brother's room, my brother came back! Her panicked sister hides in the closet and attempts to escape, but her younger brother begins to squirm! Moreover, full erection no matter how many shots you pull out! My older sister started masturbating because she was horny about her younger brother who didn't wither at all.