Not necessarily a gym story, but a locker room story nonetheless.
Went to this summer camp a while ago, they separate the boys and girls as usual. Probably 8 cabins for one communal locker room/shower/toilet facility. I'm an early riser, so I'm awake before most other campers, except for the cabin leaders. Anyways, I wanted to be the first to shower, I've got shit to do. So as soon as the sun rises, me and a friend would run to the showers. One day, one of the cabin leaders came in right after we did. 3 showers for everyone to share. My buddy was already in one, some other guy was in the middle, and I was getting ready to get in the last one. This cabin leader, probably 5' 9", stocky but buff, walks in and comes up to me. Says, "Sorry, cabin leaders get to shower before you guys". I oblige, not a big deal. So I sit back down on the benches in front of the showers, there's maybe 3 feet between the benches and the showers. The cabin leader stands right in front of me, butt to my face, maybe a foot and a half away from my face, and drops his shorts. Boom, BIG hairy ass right in front of me. I'm thinking "holy shit...what luck". He bends over to pick up his shorts. At this point, his ass is right in my face, and I'm practically hypnotized. He takes off his shirt, hangs it up outside his shower. And at this point, I'm expecting him to just hop in the shower... Nope, he turns around. His dick is right at eye level, and barely over a foot from my face. I don't even try to look away, my eyes are glued to his hairy dick. Nothing huge, but it was more than I could ever ask for. At this point, he's like wagging it around in my face...just kind of, swinging it. He doesn't say anything, doesn't smile, but just sits there for a good 20 seconds waving it a little bit, touching it once or twice. He turns around, hops in the shower, but doesn't close the curtain. So I'm just sitting there on the bench, watching this hot hairy guy lather up, bend over, play with his dick a little... and he knows I'm watching, I'm sure that was the point. He doesn't shower for long. Hops out, grabs his towel and dries off, giving me another GOOD look at his hairy ass and dick. Still, maybe a foot and a half in front of my face, like I could've leaned in and kissed it if I wanted to. He wraps himself in the towel and gives me a good long glance before walking out. Never said anything to me after, but I will never forget it.