Watching Him Cum In Panties

I remember being at my friends house and I caught her brothers friend who was 15 wearing her panties. He forgot to shut the door to the bathroom all the way and was standing in front of a mirror with his dick poking out of the panties. I watched him rubbing himself through the panties and she pulled them back and shot all over the sink. I felt my panties getting wet so I went back to my friends room and that night I slept over and silently humped my pillow thinking about him.