Sorry for the length, but this was a great event that I still often masturbate to. This is a true story.
Several years ago, when I was in my mid 40's, I was traveling to the West Coast and had a chance to visit Santa Cruz. There was a spa that features massages, but also has hottubs, cool tubs, sunbathing, and sauna among its services-all clothing optional. Many, even most, people go there and never get a massage; usually they enjoy the hot tub, sauna, socializing outdoors or reading in the quiet areas indoors. What a wonderful place blocks from downtown.
During my visit, there were about 3 dozen men and women of all ages, mostly in the hottub. I needed to sauna for a bit and entered the redwood dry sauna. It was about 8 feet across by 12 feet deep. A few very small lights gave it almost a candlelight ambiance. I took the bench on the left wall and sat nude on my towel, there was a man on the far wall nude, sitting on his. After my eyes adjusted to the near darkness, I notice he was mostly hard and that he periodically would touch himself to squeeze a bit more hardness into his erection as it went from half to completely erect.
It feels good to sit with an erection, so feeling I had the green light to do the same, I began to stiffen with the occasional squeeze, pull, or brief pump of my own cock. But, just as we both achieved very full erections, a woman entered and took the right hand bench directly across from me.
As her eyes adjusted and she noticed we both had full erections, she parted her legs and brought her left foot up to the bench level and leaned back so all of us could see each others genitals. She then spread her labia and moved her hand so each of us men had unobstructed views to her vagina.
The other guy took the initiative as he resumed touching and now holding and pumping his cock. Slowly, but pumping nevertheless. The lady watched him with interest and after a few moments, looked openly at my cock. So, following his lead I held mine and slowly pumped it. In response, she took one hand and began to circle her mound at the top of her slit, obviously stimulating her clit.
This continued for several minutes until the other man sped up pumping rapidly and came out to the floor and his towel. The lady looked at me and I at her. As she sped up her movements, I did the same. When she took her free hand and inserted her middle finger into her pussy, I held my free hand in front of my cock and came into the palm of my hand while she began to shudder and cum.
I looked at her and she watched as I took my hand and licked the cum off my palm, her eyes as big as pie plates. She smiled and caught her breath.
We each left in the order we had come in (the same order we had cum in, as well) and went back to our normal lives.