I was 14 at the time
When I was a freshman in high school, 'Erin' and I sat next to each other in English class. She was a cute blonde, with curly hair and perky little titties. After school we would call each other; and one day our conversation turned to sex. She told me that her parents had these great porn story books, and as mine did to, we started reading them to each other. As the action in the books heated up, our breathing got heavy.
I asked her if she was masturbating, and she said she was. I admitted that I was too. She started describing how she was naked, with one hand teasing her nipples, while her other hand rubbed her wet pussy. I told her how I was stroking my hard cock, almost ready to cum. We continued talking...getting louder and breathing faster; she screamed 'I'm Cumming!' as I shot my load all over my stomach.
We read to each other many times, but never talked about it except on the phone...