My brother never gets any attention from girls and just stays locked in his room, constantly masturbating. Lately, I found out he's been using my underwear to jerk off, and no matter how much I try to stop him, he won't listen. One day, my boyfriend suggested we have sex somewhere different and came over while my brother was out. Being in a new place—especially my own home—made him incredibly excited. He brought some toys and gave me a much wilder experience than usual, making me climax over and over. At one point, I glanced toward the door and saw my older brother peeping through the crack, furiously stroking his cock. I was so shocked that my boyfriend immediately ran out. Brother... why would you do something like that...?