At WGP about 4.30am on a sunday after a big night, and had the place to ourselves, so we went into the table clearing on the left and put down a blanket on the bark chip stuff (surprisingly comfy!) and got into it. The risk, being outdoors etc was awesome and in time S came with A's tongue on her clit and two fingers in her pussy. Then She got on all fours to suck A and seconds later a shadowy figure started coming ever nearer, stopping a few metres away. S's skirt was pulled right up, exposing her delicious arse and smooth naked pussy, glistening in the moonlight. A called out "you can watch closer if you like" and almost instantly the stranger was kneeling, cock out right beside us. Before we knew it, she was sucking him, then she was naked on all fours sucking A while the stranger lay under her and licked, sucked and fondled all he could reach. We told him we both love guys to cum on her, especially her breasts. And so on until the stranger asked about putting his cock in her pussy. We hadn't ever done it before, but we had talked it through, so we conferred briefly and said "only if you have a condom" He said he had one in the car, but insisted he was "clean" and had the snip so it was ok. We assured him it wasn't ok, and he ran off to the carpark. We half thought he wouldn't return, S was joking that the stranger was more turned on by A than her, and seemed disappointed on being politely stopped from stroking A due to A's lack of bi-ness. We were getting back into it, when he returned with condoms and lube, and we realised he'd jogged there and back in just his jocks and t-shirt. Keener than we thought! After a bit of sucking and general fun, the stranger rolled a condom on his quite large, hard cock and came up kneeling behind S, who was again on all fours as he lubed her still wet pussy and himself well, then after 'accidentally' trying her bum and being corrected, sliding effortlessly inside the right place. As he fucked her there in the moonlight, she hungrily sucked and licked A until he got down under her to lick and suck her breasts and nipples while reaching out to gently, then more quickly but lightly caress her clit side to side as the hard cock slid in and out. Eventually, after much fun, it died down a bit and the stranger pulled out and said he had to go. S asked if he was ok not cumming, and he assured us he was fine, and thanks were exchanged for a lovely adventure. He left, and S set about getting A (who hadn't cum yet and wasn't very hard for various reasons but very horny) hard and off. As S was lying on her back, with A sliding his hardening cock up and down outside and inside her slippery pussy lips, the stranger returned, having left behind his lube in the semi-dark. A asked him to 'help out', and he was almost instantly on his knees beside S as she sucked him and he stroked himself on her mouth and breasts in turns. The stranger was getting really turned on, and guessing his tastes, S started slowly moving her hand up the back of his leg. A started cumming a little and hurriedly got her to taste it before he spurted all over and in her pussy, and as A rubbed his cum over her belly and breasts and his cock on her smooth, glistening pussy, the stranger got really excited and as S moved her hand up to his arse crack and he furiously twisted and pulled his cock over and on her slippery nipples, he quiveringly shot a huge load all over her tits, which S and A smeared in with A's, all over her glorious belly, breasts, chest and mouth. Ironically, just after this two, then three guys came wandering by/ over but we were all done! Where were they half an hour earlier?