After the summer festival, my sister brought her friends home. Taking advantage of our parents being back at their hometown, they did whatever they wanted! They drank alcohol until late at night and got drunk, missed the last train, so they decided to stay over. When I peeked at my sister's friends sleeping together… they fell asleep in their yukata, and I could see their thighs and cleavage from the hem, making me get an erection. Thinking I would get scolded when it was noticed, but instead, I got seduced!? Of course, I couldn't refuse and ended up getting trapped!
