I work at a sports physiotherapy clinic and one of my colleagues is a woman named Naomi. She is sneaky hot. Athletic and pert with a tight body, she's in her mid-to-late thirties. She is also married with a kid. I've always had a little thing for her, but unfortunately, this true story is not about me and her. It's the next best thing.

Earlier this summer, I stopped by the clinic early on a Sunday morning just to pick something up. I was off that day, and we don't usually open on Sundays until eleven, so I simply assumed nobody would be there. Our clinic is in a large warehouse loft space, and I let myself in with a key. The first thing I noticed was the lights were on, but after taking a few steps inside, I heard something and there was no mistaking what it was.

A woman's moans were echoing from another part of the building, and my stomach immediately dropped. Part of me said, "Get the hell out of there," but curiosity overtook me.

Following the sounds, I crept through the gym area to a corridor where the physio rooms are. The rooms all have glass walls but are shielded from the inside with Venetian blinds. Through the gaps in one of them, I could tell that two people were in the midst of sex on a physio table. I got as close as I could on the far side to peer through the cracks in the blinds, and what I saw almost made my knees buckle.

I had a perfect side-angle view of Naomi reclined on the table with her legs up near her shoulders. Standing over her, fucking her, was one of her clients, this guy named Julian, who used to be a professional cyclist. I was instantly turned on beyond belief by this stud ex-athlete fucking a hot, married woman. It crossed my mind to try and record it with my phone, but I was honestly too stunned to move.

Both of them were completely naked. Julian is about six-foot-five with a lean, chiseled body covered in tattoos and piercings. As Julian pulled back with each stroke, I could see his cock was huge, and, with each thrust, the skin on Naomi's legs rippled. She sucked on his fingers while rubbing her own nipples with her hand.

I was so hard at this point, I couldn't believe it. Julian then pushed Naomi's legs back even further and fucked her harder and harder. The moans I heard at first were now even more intense, and I was actually surprised they were brazen enough to be doing this where they were.

I knew then I had to get out of there, so I hurried away. As I reached the door, I heard Julian let out a loud groan.

I went to get a coffee nearby and gathered my thoughts regarding what I had just seen. I realized I had to go back there to get what I came for, but I knew I had to wait a few minutes. Eventually, I went back, and when I did the door was still locked. To hell with it, I thought, this time if I bust them in the act, I bust them in the act.

When I entered, Julian was on a spinning bike and Naomi was on a computer at a standing desk.

"Oh, I didn't expect anybody to be here," I said, feigning surprise.

"No problem, Julian needed an early appointment," Naomi replied, not knowing I had seen everything.

What struck me then, however, really turned me on. Naomi looked hot as hell in a cargo romper playsuit, but her entire body was almost a glowing pink, presumably flush from her orgasm.

I grabbed what I needed and left, but my day was derailed. I went home and masturbated three times thinking about what I had seen.