So this just happened last night and I was not looking for it.

I got to the gym and started my normal routine, first warming up on the treadmill. Finished up there and had to take a leak. At this gym there are three urinals with full wall dividers and the stalls are fully enclosed with walls up from the floor and doors with a shaded window. If you're in one no one can see.

I go to the middle urinal and immediately get the feeling the guy at the one to my left is there for more than a piss. He's standing a bit farther away than one normally would be from the urinal. As I finish up and walk past him,, he's clearly playing and has what has to be at least 9 straight inches of hot dick. He's probably about 24 and fit looking like he just Finished a workout. There's a couple other guys waiting and drying hands and I go to do the same. The others leave and guy at the urinal is peaking around the divider giving me the eye. He pulls back and fully shows off his dick and motions to the stalls. I nod back and enter one just as someone comes into the space. My guy hangs out until it's clear and then comes into the stall with me. We quickly drop pants and start jerking each other, getting fully hard. he grabs both our dicks and jerks them in one hand while playing with my balls and nudging my hole with a finger. He won't let me suck him off but as he's ready to blow I put the head of his dick in my mouth and take three good pumps of cum into my mouth and swallow. We keep playing for a bit then dress up and he exits. I wait a few to ensure the crowd changed over and exit the stall and go finish my workout. It was a bit daring but no one caught on.