One time I had crewed on a racing yacht for an offshore regatta, and when it was over we had to bring the boat back to its home port. There was just three of us for the transfer: myself, the skipper, and his smokin' hot girlfriend. We were all in our thirties.
Being that the trasfer was over 100 nautical miles meant that we would have a night crossing. That meant dividing us three in shifts, where we would be 2 hours on watch and 4 hours off. Since there was little wind we were under power and the boat was on autopilot, so one person on watch was enough.
My watch stared at midnight. Since it was August, it was hot, and I was sleeping naked in my sleeping bag. I was sleeping on my back when midnight came the skipper's girlfriend woke me up by gently shaking my shoulder. As I came to my senses I realized that not only had I kicked back the sleeping bag in my sleep but that I also had a raging hardon. I was completely exposed. I tried to cover up but she had already seen it I'm sure... and for how long? Did she stare at it for a while? I'll never know. But is was a hot experience in more than one way!