Dan didn't know he was different from the other kids in school, he assumed that everybody could feel the same has he did. It wasn't until he was 6 or so that he finally realised that he was the only one with the gift. It wasn't much of a gift really; he could feel people's moods, without benefit of their visual prompts; he could also make people be aware of his presents. They would turn around in class and stare at him, whenever he wanted them too.
College freshman gets a ride home from a guy in his dorm. On the way they stop at the guy's house, and find his twin sister swimming naked in the backyard pool. After that things get a bit intense. Illustrated.
Another loud giggle brought his mind to his older sister Sue. She was two years older than his sixteen years and the hottest thing on the planet. She was slim with great legs and magnificent large and firm breasts that he could only dream of getting his hands on.
John and Greta, on the way to Grandma's house, take a wrong turn and end up lost. Their car breaks down in the middle of nowhere near a strange house where a seductive woman invites them in to use the phone.
When you're a twin you think you know everything about your sibling. And other girls. And yourself. Usually, you're wrong on all three counts. That said, learning what you don't know can be fun. Please note the incest code. There's not much going on yet, but that could change. If incest bothers you, skip this story.