I had previously had experiences with a couple of friends, showing-off to each other, masturbating together, but never something like this!
My house is located blocks from the freeway and there is an overpass bridge at which the stairs run alongside of the freeway bridge and then cross over to the other side. Across from that freeway there are some restaurants, stores and a gym. I usually go to the gym on Saturday noon for a couple of hours, and since its so close to my house I simply walk over, using the overpass.
So this one Saturday nearly a month ago, I had been working a sweat at the gym and decide to go back to the house. That morning I had met up with my girlfriend and had an amazing foreplay session but we were unfortunately cut a bit short due to her parent's early arrival but I was still feeling kinda horny. I get to the stairs of the overpass and notice that there is no one around me so in my horniness I get the idea to climb half-way up the stairs, drop my basketball-shorts and pleasure myself in the open air. I am in no particular hurry so I stroke my uncut 7' boner already drenched in pre-cum slowly, enjoying every second of it yet occassionaly opening my eyes to make sure nobody was walking by or could see me; the coast was clear, or so I thought.
Apparently in my distraction with my hands I seemed to not have noticed a man that was walking from the other side of the overpass and climbing down the stairs towards me. I opened my eyes to see this man about 10 stair-steps above me and intently looking down at me. I was startled and tried to clumsily stuff my dick back into my boxers as I scrambled to get my shorts back up but stopped when I heard him tell me that it was ok, to continue stroking my schlong.
He reached the same step where I was. He seemed to be in his mid 20's, short dirty-blonde hair with a 3-day beard and jeans. In those jeans I could see a prominent bulge already formed and he asked me 'do you mind if I join you?'. I simply let go of my shorts, allowing my penis to stick out straight towards the man as he began to undo his jeans and dropped them also. He wasn't wearing any underwear and I had in front of me his 9' cut cock with bulging balls and trimmed golden pubes.
The cars whizzed by above us, and I was astounded. Without even asking, the guy reached over with and grabbed my dick with a firm grasp and stroked my foreskin back. I rolled my eyes and arched my back with pleasure as I let out a restrained moan. I had already been wanking for a couple of minutes before he got there, so it only took a few seconds of his deep sensual strokes and his right hand reaching inside my shirt to press upon my slightly furry and toned abs for me to shoot five long thick ropes of cum while I thrust my hips forward into his hand.
I knew it was my turn to return the favor, but I had never touched another man's dick besides mine. His cock's head was throbbing and I instinctively grabbed a slab of my own cum which dripped from my own dick and smeared it all over his. He threw his head back and his mouth uttered low growls. I grabbed his balls and felt them wither as he wildly spurt cum all over both of us. We laid on the stairs with our sweaty and stained shirts for a minute. Then we stood up and zipped up, and parted our ways with a mere glance and a simple thank you. As I walked away, I remember seeing our jizz intermixed there at the stairs.