I've have a singular orgasm that sits atop all the others in my life. It was a one-off situation that I've never been able to replicate.
In my early 20s I worked out every day. Of course I always had to shoot a load afterward. It had been leg day and I pushed my squats to the limit, my legs were shaky as I walked home from the nearby gym. My roommates were gone and I went straight to my room and stripped off for a shower. The semi I had from exercise instantly reach full erection and slapped my stomach with a loud smack. More often than not I would jack off in the shower, but today I fell on the unmade bed.
Spit for lube and I didn't waste time. My pucker was already flaring as I started wailing on my stiff as fuck hard on. I held my balls to keep them from sneaking into my groin. My back arched, toes curled, and then it hit, a charley horse in my left calf. The searing pain of the muscle cramp raced up my leg at the same instant that my cum started to boil.
I had rarely before felt the deep feeling of cum rising as my PC muscle started to vibrate, but it had happened recently with the first couple of times I fucked my girlfriend. This time that pre eruption was pushed along by the spasming leg muscles and gave way to a full body orgasm. I have not idea just how many ropes of cum I shot that day, but not one landed on my skin or the bed. Every single drop of my juices were painted on the wall above the headboard, some as high as 6 feet from the floor.
Two other times I've had full body orgasms but my cock was always inserted so I don't know how far the cum might have traveled. But to this day, I can still recall the pain turning to ecstasy of that earth shattering load spattering all up my bedroom wall.