My mother had a summer house in Maine back in the seventies. With health problems she didn't show up one summer. Towards mid August my girlfriend, her room-mate and a friend of mine and I all drove to Maine planing to stay until about the 18th of September when we had to head back for school. I knew her room-mate well and hung around a lot with her boyfriend who wasn't with us. Her nickname was Suzy Cream cheese (thanks to Frank Zappa). She had a plush, smooth perfect voluptuous body with a pair of extraordinarily large shapely anti-gravity breasts that could not be believed even seeing them up close in person they looked so impossible, and this was before college girls might have implants.
The first thing we all did upon arrival was to take our clothing off and jump in the lake. It had been a long hot drive. Except for trips to town or when it got cool nobody got dressed for almost a month. It was record breaking hot that year, so nobody was dressed very much. In the evening we just had a big fire and stayed nude inside or to take a quick dip in the lake. Then all four of us would squeeze tightly into a hot shower together with just a candle in the bathroom and many wandering hands. Nobody knew who was feeling what but everybody was doing plenty of feeling. This started out slowly. The first night dip everybody was squeezed in and trying not to touch. Squeezed in as it were that wasn't possible. By the second round both of us guys got erect. As the hands wandered we got stroked a little and returned the favor. Things went further and further, the major limiting factor being a 15 gallon hot water heater which chased us out quickly. About the third or fourth day it was roasting, something like 95 degrees and very humid. We were all in the lake with an air mattress floating between us and we were all hanging on just floating in the cool lake and talking.
In those days it wasn't truth or dare but somehow we got onto the topic of the most public sexual experience. The other guy started out telling his story. I felt a pair of feet start working on my erect penis. I floated by body up towards Cream cheese and the feet were replaced by a hand. She kept trying to make me gasp or loose my cool for a bit and then settled into a very erotic pattern. My girlfriend told her story and I didn't really pay much attention to it. My eyes were partly closed as I drifted there with Cream cheese stroking away. She was telling her story but I wasn't really tracking it. It turns out that she was telling them a slightly dressed up story of exactly what she was doing at that moment. They all clued into what was going on and I didn't even notice, in that building erotic charge. With a few minor changes of the air mattress floating angle, unnoticed by me, Cream cheese's handy work was in full view of everybody. She was giving a blow by blow description of how my penis was throbbing in her hand. I lost track of where I was and was moaning a lot. Suddenly I reached that point of no return as my penis started tightening and throbbing. As my semen started spurting out there was suddenly a cheer and I opened my eyes to find everybody else gathered around intensely watching my spurting penis and reaching to feel it as it squirted. What an intense orgasm. It was really good.
That night as Cream cheese was lounging in front of the fire with her legs splayed open I sat down beside her and laid my hand over her labia and said 'Your turn'. She was instantly wet, she must have been thinking some horny thoughts. I slowly rubbed and massaged her whole vulva. I started lightly running a finger between the outer labia brushing her inner labia and clit lightly. She started squealing and moaning. After a bit she had her first on display shared orgasm as she bucked around and screamed. Each of the other two had theirs in turn. Within a week all three of us were stroking the object of our attentions and all had shown each other how we each masturbated and orgasmed. We even had group four way orgasms all at the same instant each person being stroked by somebody else. It was really most excellent. I remember one day the caretaker walked in unexpectedly, maybe 20 years older, and his eyes just about popped out of his head when Cream cheese walked around the corner of the deck and he was on the ground. He got a close up pussy level view of her very aroused pussy and an underside view of her anti gravity breasts.