Back in the early summer I saw Fran, my 35 year old, wife being fucked by another man for the first time. We'd been to a wedding in South Wales and were driving home, quite late on the dual carriageway between the M4 and Monmouth. I hadn't been drinking but she had made the most of the bar. We'd already stopped at a service area near Cardiff when she announced she needed another piss. I knew there was a lay by with a toilet in about 10 miles so put my foot down. We pulled in, empty except for two lorries, the cabs in darkness, parked opposite the loos. We parked near them, next to the toilets. She rushed for ladies, moments later reappearing hopping from one foot to the other, telling me they were locked and wanted me to check the mens. All clear, in we went and I stood outside the cubicle listening as she took a long piss. All went quiet and I waited, calling to her, asking if she OK. “Fine, is there anyone about, check outside” she called back. I knew what she wanted, a few drinks make her randy and it wasn't the first time we'd stopped and fucked on our way home after a party or night out. In a lay by or car park usually rather than toilets. I was only gone seconds, all clear luckily, because when I turned she was standing with her skirt around her waist, panties around one ankle, her top and bra thrown over the cubicle door, one hand between her legs fingering her pussy. “Quick she said, Fuck me, no one's about” disappearing back into the cubicle. Seeing her behave like that I couldn't have cared if there'd been a coach pulling in. She was bent over the toilet. One hand on the wall, her legs spread the fingers of her other hand still rubbing her obviously soaking cunt. Talk about instant erection. I took my cock out and entered from behind, holding her tits, fucking her while trying to listen out in case anyone came in. She moaned and squealed, getting louder and louder as we fucked. I told her to keep the noise down to no avail, if anything she got louder. It was probably only two or three minutes but she started to orgasm, much more quickly and certainly more vocally than normal, her pussy muscles seeming to grip my cock as she came and I shot my load in her belly. I pulled out, put my cock away and stepped back. Fran stood and turned, following me out, skirt still bunched around her waist, panties still around her ankle, my spunk running from her pussy. She wasn't looking at me but over my shoulder. I realised there must be someone there, wondering who, and why she wasn't covering herself. Instead she asked why I hadn't told her we were being watched, a look on her face, not of embarrassment, or guilt but lust. I turned to see who was there, a bloke, one of the lorry drivers, was by the entrance, cock in hand, stroking an impressive erection, at least eight inches and very thick. “Fancy a bit of this Love?” he asked. I turned back to tell her we ought to leave, expecting she would be dressing. What I found was Fran, had moved so he could she her better, and was rubbing her pussy, pushing her fingers in her hole, then lifting them to her mouth licking the spunk off. I must have frozen for several seconds in shock until she started to push passed me. I grabbed her arm, “What the fuck are you doing?” I hissed. “I just want to touch it. Let me. Pleaseee” in the voice she uses when she really wants something. I nodded and she went over to him and reached for his prick, taking it in her hand wanking this complete strangers cock. I was to surprised to say or do anything. Not just that, even though I'd just fucked her, my prick was stirring, starting to get hard, as I got aroused and excited, she looked so horny and dirty, tossing him off. She bent to get a closer look. The guy put his hand on her head and pushed her down. “Suck it Slut” he demanded. She hardly glanced at me long enough to see me nodding my head, unable to speak. I doubt it would have made much difference what I thought. She crouched down, pulling him closer and took his cock between her lips and began giving him head. I noticed she'd opened her legs, wanking her cunt with two or three fingers, her other hand holding his balls as she sucked him. She seemed to suck him for ever, but probably only 3 or 4 minutes, her hips moving on her fingers as if she was being fucked and close to cumming. The guy looking down at her and could tell she was close, pulling his prick from her mouth. “You need fucking. A hard cock in your cunt. Come on I'm going to fuck you outside” She stood, took his arm, pulling him outside she was so keen for him to fuck her, not appearing remotely concerned she was almost naked. She ignored the lorry parked nearby, the driver watching from inside the cab, vehicles passing as she hurried towards the picnic area. He told her to sit on a picnic table on a grassed area off to the side under some trees. She perched herself on the table and opened her legs, there wasn't much light but with the lights from traffic passing only yards away I could see her cunt gaping open, shining with her juices and my spunk. He got between her legs, hands on her knees, spreading her wider. I moved to one side, watching as he slid his cock along her gash a couple of times. Then he shuffled closer, holding his prick aimed at her cunt, his knob end penetrated her hole, parting her pussy lips and he rammed his prick straight up her. The remnants of my spunk were coating his prick, more displaced, pouring from her cunt each time he thrust into her,. He reached for her tits, squeezing them in his hands, pinching her hard nipples. “Fuck me, Fuck me harder you bastard” she groaned, throwing her head from side to side, lifting her bum off the table to met his cock ramming in and out of her cunt. I'd never seen or imagined she could behave like that, it was like watching another person. He can't have slid his length in and out of her cunt more than 7 or 8 times before she orgasmed, he just continued fucking her. She kept hissing at him to cum inside her, almost begging him to give her his spunk as she came for a second time. She kept saying how good it felt, how big his cock was, telling him she'd never felt her cunt so stretched or well filled. He fucked her for about 10 minutes before he came, seeming to pump jet after jet of spunk in to her wanton cunt before pulling out and wiping his cock on her skirt. He didn't say anything to Fran, just commenting to me how lucky I was to have such a Slut for a wife as he walked off to his lorry, leaving her laid on the table, legs open spunk pouring from her well fucked hole. I ran into the toilets and fetched her top and bra, returning to find her sitting up. “I've wanted to do something like that for a long time” she said slurring just a bit, pulling her skirt down from above her waist, kicking her panties away, before putting her top on and handing me her bra as she got in the car. She slept most of the way home and we went straight to bed, leaving me thinking about what she'd said. I lay awake for a while wondering whether she'd been more drunk than I thought. I had a good idea how much she'd had to drink and whilst she'd been tipsy, was certain she'd been fully aware of what she was doing. The next morning I was woken by her showering then climbing into bed and giving me a blow job, letting me cum in her mouth. When she'd finished she sat crossed legged and told me how much she'd enjoyed what had happened, explaining that it had been a secret fantasy for some months. She slowly worked her way round to wanting to know what I thought. I told her that it was the horniest thing I'd ever seen and I'd enjoyed watching her. Her face lit up, she asked if I'd heard of dogging. I told I I knew what it was, listening as she told me she had overheard a woman at work telling someone about it, enthusing over being watched fucking and being fucked. “And you want to give it a try?” I finished for her. “Can we? Soon” she said getting out of bed to fetch her Laptop to show me the SH website. I was as enthusiastic as her after looking at the stories, finding that there were a number of possible locations relatively close to us. How could I possibly refuse her request. Just one final thing. The lorry driver described her as a Slut. Five months on she has proved beyond any doubt he was right. I don't know how she managed to keep it hidden for five years. Maybe she didn't even know herself and the circumstances that night were the catalyst which released the Slut within. Whatever the reasons she's now an enthusiastic and willing Cum Slut . Her descent into Slutdom has been incredibly rapid, total and without inhibition, to the extent that she has played with another woman so there's more to tell.