This happened just recently. With three friends (one couple and one boy) we stayed away during the weekend out of the city, in the small village house. There was just one bedroom and only two queen size beds in, and since the couple wanted to sleep on one, I had to sleep together with the other boy. It was little weird for both of us, but we had a lot of fun that evening, so we accepted this ´uncomfort´ as kind of tax for the nice party. We slept in T-shirts and the underpants to avoid any skin touch during the night, because we were covered by just one blanket.
It was very late night when we got to bed, so the couple on the other bed, which was just several feet from us, thought that we were already sleeping and started making love. They weren´t that loud but there was a certain noise making me sure what was going on. Ironically, none of us was sleeping yet I started to be terribly horny, so I moved my knees up very very slowly to make access to my penis and at the same time I took my pants a little down. Soon I started to jerk off, still very slowly when I found my ´bed-mate´ doing exactly the same. Soon his knees were holding the blanket really up so I could see down there how our right hands are both working very hard. At some point the bed shook a bit and I heard some giggles on my left on the couple´s side of the room and then an accidental moan on my right side and then we all started to laugh loudly. For several minutes after that we were just listening to the sounds of their sex and our masturbation, what was very arousing, they all came, but for unknown reason I couldn´t even when they were waiting for me and somehow encouraging me too.
Finally I went to the bathroom because I needed to finish myself. It took me some time when the girl came quietly, telling me she wanted some more. She didn´t show me anything, just put her hand in her pants and in a second she had a wonderful orgasm, immediately followed with mine.
We all masturbated again that night, the second time I could reach my orgasm with them all around much more easier.