I was at a local park hanging out with a group of friends and needed to pee so I went to the public restroom. It had a trough urinal, I stepped up and started doing my business. Before I finished, I heard a guy stepping in next to me. I glanced his way and my eyes darted down to see his flaccid shaft (it had to be at least 10 inches and he couldn’t get his hand all the way around it). I was amazed and must have let my eyes stay focused on that huge cock way longer than discretion would allow. When I finally looked up, he was just smiling at me and said that he didn’t really need to use the restroom. I didn’t even put my cock back in my shorts, I just dropped to my knees, grabbed that cock in both hands and took as much as I could into my mouth. After a few minutes, he was fully erect and throbbing, leaking pre-cum like crazy. I got to my feet and dropped my shorts, leaning over against the wall. He stepped up, and using his pre-cum, lubed my hole, inserting a finger to open me up a little. He then stepped in & shoved that whole monster cock up my ass in one forceful stoke, lifting me off the floor as he did so. It was fucking awesome…. After about 20 or 30 similar stokes, he started pumping what felt like a gallon of cum deep in my ass. I shot my own load into the urinal as he pulled out of my quivering hole. As I was trying to regain my composure, he grabbed my shorts, wiped his cock clean and left, swinging my shorts from his finger. After about 10 minutes, I realized that I was naked from waist down in the middle of a public park, at least 500 or 600 yards from my pack that was with the group of friends I had come to the park with. They had all seen me naked before, so that would not be an issue. I decided to just act casual and hope for the best. I did get a lot of stares on the walk across the park, but no problems. When I reached my group they just shook their heads and someone tossed me my pack. As I was digging in the pack for more clothes when someone asked what was on my legs. I looked down and saw that on the walk back, cum had started flowing out of my ass and I had clearly visible trails from my ass to my ankles down both legs… So I told them want had happened.