I recall having read a story in the past about masturbating with (or on) poles and ropes. It reminded me of several youth experiences of my own, as I had a particular sensitivity to those items myself (at least when the mood was right).
During my Junior year in high school, gymnastics was taught as one of the required elements in my PE class. This involved everything from balance beam to floor exercise, vaulting, and rope climbing. For the rope climbing exercise, we had to demonstrate that we could climb about a 40-foot rope (the height of the ceiling) and back down again.
Having practiced some on the rope, I knew that brushing up against it through my sweat pants while using my legs to climb would always produce a teasing feeling in my penis that would quickly lead to the start of an erection. It was an exciting feeling and made climbing the rope itself a distraction. Usually, the slower I would climb, the better it felt.
As good as it felt, I was always aware that my full boner might be obvious to others and/or that I might cum at some point, so I didn't always go to the top. However, eventually, we had to reach the top as part of our 'test' on the event, so I knew that had to be done.
A day or so before testing, I began a climb with the usual spotter/holder at the bottom. Immediately I felt that familiar tingling in my balls and the stiffness of my cock began to force the shaft up against my leg. As the head of my swelling penis was pressed lightly against my inner thigh by the next climbing stroke I knew that an erection could not be stopped. By the time I was 10-15 feet or so up the rope, my penis was fully engorged, which added to the sensitivity factor.
As I moved further up the rope, the slight fabric of my sweat pants was not much hinderance to the friction of brushing up against the rope. With each pull of my hands, I could feel my arm muscles get a bit weaker as the focus began centering around the pleasurable sensations near the head of my cock. Each tug at the rope was both difficult (from a climbing perspective) and yet enticing as my pleasure intensified.
Once I reached about 30 feet (or 10 feet from the top), I could tell that climbing much further would lead to the inevitable. Of course I went on, sliding and pulling myself up the rope another four feet. As I reached my hand up again and pushed with my legs a bit, I could feel the welling of volume within me... I paused only briefly and reached up again with the other hand to pull myself within a couple of grasps of the top. As I slid my legs up to that position to regrip for that last bit of climb, the friction was too much to take. As I secured my hold on the rope, I felt the tensing muscle at the base of my penis squeeze ever-so-hard as I began filling my pants with warm, white semen. A most pleasurable orgasm ended about 10 seconds later as I struggled to maintain my hold on the rope.
After re-focusing my thoughts, I did climb the last couple of arm lengths to touch the top... at which point I promptly made sure that my sweat jacket was pulled down over my pants as much as possible (as the wetness was sure to show through eventually). I then slowly lowered myself back down the rope and excused myself to the locker room. The intensity of that experience (and others like it) still stick in my mind.