I read something similar like this on the female-technique pages, but it also works for boys:
I think I was seven years old when I discovered that I had 'funny feelings' when climbing a tree. I discussed it with a friend of whom I expected that he would know what I meant, and he did. During that summer, there was a lot of tree-climbing!
The essence of the technique is that you try to climb with your legs, without(!) actually climbing. You only make this upward climbing-move with your legs, pulling your knees upwards and let go again. Your hands stay in the same position and carry your weight.
Of course, this technique is more comfortable when you are slim (or strong).
This technique gave me my first 'rudimental' orgasms as a young boy, and later hundreds of very intense 'real ones.' The feeling was so good that I started to do this at home also, with the bedroom-door. First (like with the tree) with clothes on, and later, when I was a bit older, naked. The door-technique: when naked, it is better to lube your penis first. Then, clean your hands, so there is no lube left on them. Open the door and grab the doorknobs. Place one leg at each side of the door. Bend your knees and then pull yourself up against the door so that your weight is carried by your hands. Make a constant short (approximately 10 cm, or 4 inches) pulling movement with your hips and knees, up and down, up and down. You'll reach a very intense orgasm amazingly soon!