28 now, 11 then
When I was 11, I began to get curious about boys. I knew they were different, and had heard some things at school, but I wanted to know what a boy's 'thing' looked like. One Saturday my parents went shopping, leaving my 14-year-old brother in charge. It was a rainy day, so we stayed inside. We watched TV for a while, and I got up the nerve to ask him what his 'thing' looked like. 'You mean my peter?' he asked, looking surprised. I just nodded. 'Well,' he said,' I can show you, but only if you show me what you have, and you have to promise not to tell anyone.' I quickly agreed, and after some debate over who should take off their pants first, we agreed that I would. So I took off my pants and panties, and he had me lay on the floor and open my legs. He got down on the floor and put his face up close for a good look. I could feel his breath on me 'down there,' and I felt tingly as he explored a little of my slit with his finger, tracing my lips.
After a while of this, I said, 'My turn.' He wasn't hestitant any more, but eagerly dropped his pants, and I was looking at my first erect penis. I held his balls in my hand, and closely examined his 'Peter' as he called it. I was fascinated by the way it bounced slightly with each heartbeat. I traced his 'thing' with my finger, and he showed me how he stroked it 'to make it feel good, and squirt cum.' He asked me to stroke it for him, and I did (he told me later no girl had ever touched him before). Before very long at all, he tensed up (I still remember how his balls tensed in my hand) and shot about four long ropes on cum on the floor, leaving off with some dribbles.
We may have played more, but time was running out, our parents would soon be home. So we cleaned up the cum and went to back to TV, acting like nothing much happened when they returned shortly after.