This happened while backpacking in Canada
Having been staying in youth hostels for the last three months it had been sometime since I had found the privacy to J/O. This changed one night when sleeping in a mixed dorm, I woke up to hear some deep heavy breathing, I opened my eyes to see on the bunk next to mine the outline of a female body as I squinted in the half dark I could make out one of her hands on her breasts, the other under the covers, her breathing was getting deeper.
I then became aware of a faint squelchy sound (the sound of fingers in a wet pussy) by this time I was rock hard and just had to jack off. I tried to start off slow and quite not wanting her to know I was watching. Her hips started pumping and I pumped my cock to her rythym as her hips pumped harder and the sound of her wetness got louder she let out a muffled moan.
I was now so horny I didn't care if she caught me as I felt the cum welling up I started to moan with her. We both started muttering that were cumming at the same time. It was the best orgasm of my life.