[MFN]

Both with my then-GF:

The first was on an isolated beach, where some folks stripped off while others remained clothed. It was far enough from home that we probably wouldn't be discovered by anyone we knew. This was important because she held a very responsible position in our community. Once on the beach, we chose a hidden cove, stripped off and stretched out on our blanket. Exhausted from the long drive, she fell asleep while I read a book. Her most comfortable position for sleeping was always on her back, legs wide apart, knees slightly elevated. All was very private and quiet. While she was still asleep, one leg loosely flung over mine, three couples approached along the shoreline, all clothed. As they got closer, I recognised them as two members of her board and their two spouses, and two of her employees. GF knew them all professionally; I knew them only through her. As they got closer, they recognised me and walked straight up to us. GF was still asleep, legs splayed out, one leg over me, preventing me from moving to reach for a covering. Now within talking distance, they engaged me in conversation, and all I could do was remain in place and chat with them as the six stood there looking down at our nakedness. They unfolded their beach chairs in an arc around our feet, obviously intending to stay for a while. Conversation was polite, nothing about us being nude and them clothed, nothing about how they could have counted her pubic hairs if they'd wanted to, nothing about now knowing what their boss's clitoris looks like, nothing about my growing erection; they were just out for a seaside hike. For me, it was a massive turn-on, having my GF displayed so brazenly to her professional associates. Mercifully, her leg over me partially blocked my erection from their view, but, just on the edge of cumming, I had difficulty maintaining a casual conversation.

The other event was on a cruise. The deck above the navigation bridge, being out of sight of other parts of the ship, was set aside for nude sunbathing and even featured a hot tub, which was popular after the sun went down. It was a pitch-black, moonless, warm night, and GF and I were enjoying the hot tub. I wanted to visit the nav bridge to learn a bit about ship operations, so I slipped on shoes, shorts and a tee shirt and left her in the hot tub. Permission for the bridge visit had been set up earlier, so I went below. It was totally dark there, except for the faces and uniforms of the officers dimly lit in the glow from the various instruments and radar screens. All was quiet except for the hum of the engines, the sound of the hull slipping through the water, and the occasional whispered command or observation from one of the crew. After quietly chatting for some minutes with the officers, I could just make out the shape of a new arrival, standing silently against the rear bulkhead. Nobody else took notice, but I soon was aware of feminine shoulders and head, breasts and nipples. Each sweep of the radar screen bathed this new person in a soft green glow, to be repeated about twenty seconds later on the next sweep. As my eyes adjusted, I could differentiate her dark pubic hair from her light skin, and I realised that not only was this my GF, but that she was totally naked. Soon the Captain noticed her, and being the gallant gentleman, invited her forward and offered a tour of the various navigation stations, never implying that her nakedness might be a distraction. I stood by as the subdued pilot lights of each new dial bathed her in a soft glow. I watched as she bent over the chart table, her small breasts awash in the dim red light of the table while her backside was swept in green from the radar behind her. Watching her make her way to each station on the bridge, totally nude and chatting with each of the crew members, for about twenty minutes I stayed on the very edge of an orgasm. I think being in the quiet darkness made the whole scene much sexier than if there had been daylight, because while sunlight may speak of social nudity, silence and darkness speak of sex. It was as though she were presenting herself not just to be looked at, but ready for sex.