Storeroom in a County Hall, in a (private) hospital ward when the then GF was visiting me. Late night in the stand of my local football club that was hosting an end of season function. Few risky, kind of, like a park, uni common room, car. Most risky and so unique was when a teenager in my room when my folks were still in, one off as it wasnt worth the stress of it!!

I know a young guy that told me three or four jocks had sex with this young teacher in the equipment room by the gym. They were 18 and maybe she was 22. He said they didn't do it all at the same time, they were just different guys she banged. They never got caught and apparently she moved on from younger guys and got married. Back in the day she probably would have been fired, but not had to go to court like they do today although from what I understand all the guys were legal age. I didn't know her well, but she was pretty cute and the guy told me this went on for a few months with like 4 different guys.

If I could give you two thanks I would because when you're supposed to be working your having fun is be the best

Same here except it was a supervisor and we was in the storeroom behind some equipment. Something must be in the sauce

Community shower
 

Before we were married, my wife and I used to have sex in the community showers of the men's barracks where I lived. There were stalls with ill-fitted curtains, but it was more private than my room.

On the hose bed of a fire truck

In the back of a military truck on top of some cam nets. Or in a hedge. I don’t know why she wanted to get fucked in a hedge but I wasnt going to say no.

IIRC there were two other people that reported the same thing earlier in this thread. That makes four of us which either means it is fairly common or a high concentration of kinky firefighters are on OCC.

ON THE LAKE
 

My fantasies have often included pools, lakes skinny-dipping and boats. Sadly though, reality has always been a little less intense than fantasy, perhaps because outdoor sex gives you more things to worry about. The image of sparkling clear pool water is very titillating, but it has always been that little bit too cold. And cold water shrinks more than your ambitions. Boats have always been a turn on for me, but harsh reality says that a boat cabin is just a cramped version of your own bedroom.

But once, just once, I managed to get most of the fantasy jigsaw in place. Dorothy and I were on a Hobie Cat on a warm tropical lake. The air was kind and the winds were light. A sailboat is a magical thing, because if you get it sailing on a fixed course with the sails cleated, the sailboat is a machine with no moving parts, yet the whole thing is moving across the water. When we got far enough from land to feel private, we stripped off and sailed nude for a while. She was young and beautiful and I was young and horny, so we started making out and eventually I asked for more.

The trampoline of a Hobie cat is like a big, wide camp bed. The sails were cleated in, so all I had to do was steer the boat. Dorothy lay back on the woven trampoline. I climbed on like an eager missionary, gripped the tiller extension between two toes on my left foot and managed to stabilise it on a fixed course. I was super eager, so penetration was easy and we continued like that for a few minutes with my butt rising and falling to the rhythm of the waves. My erection would fade if I took my mind off the job, so I got very focussed and super intense. When I'm like that, I have a wonderful time, but I can't last.

It wasn't Dorothy's fantasy. Her butt was against the un-cushioned trampoline and she was supporting a bouncing man whose mind was on matters of navigation. Very erotic for me, but not much cop for her. Dorothy's idea of a good time included privacy, a comfortable bed a gentle pre-amble and an attentive, caring lover. I tried to be like that when we returned to the Hotel later that day. I think I succeeded and there was some vocal evidence to support my opinion.

In a Row Boat on the shore!
 

I went with a few buddy's to visit a few of our girlfriends, that had rented a Cabin on a lake for a week and we ended up staying for the night!
At night we all found places to sleep all over the place, but next to our girlfriend. At sometime going into the night my girlfriend woke me up and said she was getting Hot, but I can't remember if we both were in a large sleeping bag or under a blanket? She asked me if I would walk outside with her and I did, going to a row boat they had laying on the sandy shore line! We sat in the boat and in a few minutes started making out!
The next thing that I knew, under the Moon light and in that Boat we had some great SEX!
After rocking that boat on shore, we went back inside and it appeared that everybody else was still sleeping and didn't view Us!
We all got Up in the morning, but nothing was said so I guess it worked out well and we had more Fun with the girls till us guys went home!

:D