I grew up in a semi-rural area that had woods and houses all mixed in. A few houses up the street was an older couple whose grandson was my age and he visited them quite frequently, as he lived only a mile or so away.
He built a little box or getaway in the woods behind his grandmother's house, and then invited me to come see it. It was tiny, not even big enough for us to do anything other than lie down.
So we were lying there just chit chatting when out of the blue he said, 'Ill jack you off if you'll jack me off.'
I said, Huh?' because I had never heard that phrase. He figured that out quickly and told me to pull down my shorts, and then he pulled his down.
He said he learned about this from the cub scouts and it feels great.
So he got my dick hard and then spit on it, he said because it keeps it from burning. So he jacked me and then I told him to stop because I had to pee really really bad. But he just kept going, telling me that I would feel something different in a minute.
And, sure enough, I felt something and the clear spit in his hand turned white. He told me I had shot off and the white in his hand proved it. I had just had my first orgasm at another's hand!
It felt so good that I practiced more when I got home.
So the masturbation graduated to mutual masturbation, especially when he found his uncle's stash of adult magazines.