Older sis visited from the city today. We studied calculus together and she kept leaning over my shoulder, her long hair brushing my neck. Her tits were so close I could smell her perfume. I got so hard I had to keep my textbook on my lap the whole time. When she hugged me goodbye, her body pressed against mine and I almost came in my pants. Now I'm alone in my room with my cock throbbing, imagining what it would feel like to slide it between her perfect breasts. I hate these thoughts but I can't stop them.