This happened a little over 3 years ago.
Like many boys our age we often made jokes about masturbation, but the day I actually walked in on my friend Tim with his hand on his cock watching porn on the computer things changed. Within a week we were blowing loads in tissues and socks while watching porns together after school, before our parents got home from work. If it was at your house you'd get a sock, and if you were at the other's house you'd use toilet paper or tissues.
We were talking about the difference one day, how the sock gave so much more stimulation to the dick head but you didn't get to watch the semen burst from your penis. We were both cut (and a little under 6 inches) but we both had a decent amount of skin so we always masturbated dry. His rod was bent slightly upwards in the middle and always came rapid fire, not a lot of distance but it let out the shots almost twice as fast as mine did. We decided that seeing yourself cum is fun, but a stronger orgasm is better. This led to us talking about what gives us our strongest orgasms.
After sharing the techniques, we pledged that next time we would try each other's favorite.
The next Monday, after getting home from school, we went to his house to his room and watched a bunch of porn clips, slowly stroking ourselves without trying to cum, just trying to get really hard. Then we went up to his parent's bathroom to try the techniques.
I gave him a condom I had taken from the school nurse's office, and he turned on the hot tub.
My technique: put a little lotion inside the tip of a condom (enough to fill the tip), lube your whole dick, then put on the condom. Then grip your cock head and masturbate using the condom like it's a foreskin, sliding it up and down.
His technique: put your cock head in front of the jets of the hot tub and then masturbate like normal, just keeping the head in front of the jet.
So he sat on the edge of the hot tub and I sat in it, and we did our thing. The techniques were good. It only took about 5 minutes. Instead of only breathing hard or little gasps as our cocks spasmed, we both came with loud groans. He filled the condom with his semen and I blew my load into the water of the tub. I was a little light headed afterwards. Normally after we cum we go and do something else, but this time, after doing a little clean-up, we were so spent we just went down to his living room, laid on the couches and fell asleep.