3 half brothers who's really physical and casual between eo, but have their own lovers. Oldest bro with the middle's friend, the middle one had unrequited feeling to the oldest but then got his own (which i can't tell what relation at first bcs he looks somewhat like the oldest bro so i was misled for a good chapter there), the youngest is with his teacher. Again, all three bro are very openly casual about their sex lives among eo, so. Ofc it includes exhibitionism and voyeurism
San Kyoudai, Oniichan no Koi