My name is William Wilkins, and at the age of 15 I had an experience that wasn't just "out in left field", but clear out of the ballpark.

Like most guys about that age, I was stuck with the trials and tribulations of puberty. Unlike most guys, I had the benefit of having grown up with a sister (Eva, which I shortened even further to just "Eve", just a bit more than one year older than me) that I got along with pretty well. Not that we were best buddies, or anything, it was just that our folks hadn't tolerated any kind of fighting or arguments between us as we grew up; as a result, we were a lot more tolerant of each other's foibles. Not only did we play a lot of "show me yours and I'll show you mine", but even got to be comfortable with playing "Doctor" to a degree that I doubt our folks would have approved of. That attitude continued even after each of us started puberty, so that seeing each other only in our underwear or half-nude (or completely so when I could manage it) was no big deal of either of us; it wasn't that each of us didn't have other friends, but simply that we'd grown up that comfortable with each other. Since there were hardly any kids our ages in the immediate neighborhood, that was a good thing.

Our relationship was such that neither of us ever said anything (even to each other) about the small holes that developed that gave each of us a viewport from our respective closets into the others bedroom. I got plenty of chances to see how Eva's physical development compared to that of her friends during sleepovers, and even learned how girls masturbate; I don't doubt that Eva had much the same experiences.

That was how things worked in our house right up until a new family moved into the neighborhood in the middle of the Spring semester at school, of all things.

Naturally enough, what really got my attention about them was that there was only one kid: an attractive girl about my age. She wasn't as physically developed as my sister, but still clearly female; she had long, glossy black hair, trim legs, an ass that I immediately fell in love with, and a pretty face with slightly full lips and grey eyes. It didn't take long to learn that her name was Charlene Johnston, and that she was just a few months younger than my sister.