When I was 14 years old and very curious about the opposite sex, my 13-year-old cousin came to visit for the week. On the third day of the visit, his parents and mine went on a shopping trip to a mall in a neighboring city, leaving us to ourselves for the day. I 'accidentally found' my parents 'Joy of Sex' book, and we looked at it together in my room.
After a short while, I said I had to go pee, and he said he did too. So I said, 'Let's watch each other.' We went to the bathroom together and he went first. He was excited and when he pulled his penis through his fly, I saw my first hardon. It was about five inches, which I later found out was a good size for his age (I wonder what it's like now). He had a hard time peeing since he was hard, but managed to do it. Then I sat and went.
We went back to my room and he said it wasn't fair because I saw his dick, as he called it, but he couldn't see anything because I sat down. So I said, 'Let's both pull down our pants.' He quickly agreed and we did. I lay on my bed and he inspected my virgin pussy up close, lightly petting me. I was getting excited, and said 'My turn.'
He lay back and I examined him closely, feeling his balls and his 'dick.' I asked him if he played with it and he blushed and nodded. I began to stroke it like I'd read about, and said, 'Like this?' Again he nodded and I continued stroking him. After a bit he started thrusting into my hand and soon I saw his balls tense; then he was shooting cum into the air, another first for me.
I wiped my hand off and smiled at him. Since he hadn't made me cum, I sat back and said, 'Watch how I do it,' and fingered myself to my best orgasm yet. By the time I was finished he was hard again.