When I was a kid we lived in a cramped flat in a big eastern city and I had to share a bed with my older brother, Paul. Around the time I turned 13 (and he was then 15) I began to have wet dreams, but had no idea what the sticky stuff was that was starching my pyjamas and leaving a crust on my belly. I knew nothing about sex and innocently asked my brother if he thought I was sick. He laughed and said it was nothing to worry about but if I wanted to avoid the mess he could show me how.
After breakfast our parents went off to their store and it being summer, we had no school to attend. We sat on the couch in the living room and Paul told me to take off my shorts and underwear and sit beside him, and he did the same. Then he had us both remove our T shirts so we were completely naked.
Paul gently touched his own nipples until they became stiff and told me to do the same to myself. At first it felt queer but after a few minutes I got this funny feeling in my crotch and my penis began to roll around a little. Then I noticed that Paul's penis was sticking straight up through his thick forest of hair.
Then he spit in his hand and told me to do the same and told me to do just as he did, and he began rubbing his penis. I did so and again it felt funny but soon it began to feel like nothing I had ever experienced. We kept renewing the spit in our palms and rubbing and then Paul slid onto the floor and turned so he was on his knees facing me, and putting his head between my knees he watched what I was doing and kept urging me on while he kept rubbing himself.
Suddenly a feeling swept over me so intense that I thought I was going to die, and I squirted thick white gobs from my penis onto Paul's face. I started to apologize but he laughed again and told me not to worry, and he licked one of the gobs that rolled down his face to his lips. He stood up then and shot his white gobs on to my face. It smelt like the sea and tasted mildly sweet and salty.
After that, we showered and then Paul told me all that he had learned about sex from his friends, which fortunately turned out to be accurate. From then on we had many sessions like this, including in bed at night, until he went off to college. We have never talked about it since then.