When I was a kid, the neighbor kid across the street and I used to play with glans rubbing, rubbing the palm of one’s hand over the tip of the other guy’s dick. We were still too young to realize that using some sort of oil would not only make it smoother, but would actually intensify the feeling.
I found a darkroom timer in the trash. I didn’t know what it was at the time. It had a clock face, and electrical outlets. It could be set for an amount of time and would buzz until the time was up. Somehow he and I got the idea to set it to 7 minutes, and then one of us would rub the other’s glans for 7 minutes. We had done it for a minute or so at a time before, and it was delightful torture, but never seven whole minutes.
First, he did me. Although squirming like crazy, I also had that delicious combination gonna-cum, gotta-pee feeling that only comes from this particular technique, but neither happened. It started to sting toward the end. I didn’t think much about it.
Then I did him, and he reported the same experience. When it came time to jerk each other off, we noticed both our glans were red and blistered. Needless to say, we wanked each other very gingerly! It took several days to heal.
Picture above is my penis today. As you can see, no permanent damage was done.