I was an avid hiker when in college. My girlfriend Jessica and I would go nearly every weekend. The only problem was her best and bitchy friend Cindy would almost always accompany us. Actually, since Cindy was cute and sexy, the real problem was that neither she nor my girlfriend was interested in group sex.
Well, my girlfriend and I were very interested in sex with each other, however, and our basic aim was to do it as much as possible wherever we happened to be.
This was generally not a problem when hiking, as after pitching camp, we would simply skip off into the woods or behind a rock and suck and fuck while Cindy twiddled her thumbs or perhaps other body parts.
Well, one night after hiking nearly 20 miles, we finally got to the top of the mountain, the lone campers up there. I fetched water, cooked dinner, and strung up the remaining food between two trees. And though it was spring, it was cold as hell up there at night, so we all wriggled into our sleeping bags under a two-person tent. Three people in one two-person tent = extra cozy.
Something came up. My dick, to be exact. My girlfriend was also horny, so it was really no problem slipping my hard cock into her wet pussy, as we'd zipped our bags together and were nestled in a spoons position. But, in so doing, we did not want to awake Cindy, who was literally pressed against me, so we had to keep the vigor to a minimum. Less vigor = longer fuck.
Well, we finally had orgasm on the radar screen when Cindy awoke, but we were not about to stop fucking at that point. Cindy kept saying, in a raspy whisper-shout, to stop, stop, stop, and some mumbo-jumbo about something else I didn't quite hear while whacking my back with her fist.
To stop this infernal coitus interruptus, still inside our sleeping bag, I rolled back, careful to carry Jessica with me and not slip out of her pussy, in order to pin Cindy in her bag and squash the breath out of her. That body-mute worked quite nicely, and Jessica and I came big time shortly thereafter.