We set off as soon as I'd finished my morning work, livestock don't recognise birthdays, or weekends, and we were at the coast by mid-morning. First stop was the ice cream stall a tradition no matter what time of year, but welcome in the late August heat.

A stroll along the prom, busy but not crowded led us to our favourite shop "Niks and Pieces" where we regularly added to my wifes' collection of erotic lingerie. As today was my birthday I got to select the outfit and a peep hole bra and matching crotchless knickers was soon wrapped up discreetly by the shop assistant.

Back at the car I suggested she change into the new gear but got rebuffed initially. Pointing out that it was my treat day softened her resolve and she pulled her skirt up to enable her to swap her knickers as she sat in the car. The new bra posed more of a problem as her upper body was visible to any passers by. Luckily we'd brought coats with us in case the weather changed and she draped hers around her as she wriggled out of her T-shirt and exchanged her bra for the new one.

She held out her hand for her T-shirt but I pointed out the revealing nature of the peep hole design and suggested wearing the coat to cover her modesty.

We drove along the coast to a supermarket where we planned to do some grocery shopping before we returned home. As we exited the car she fastened the toggles on her coat and I commented on the lack of evidence of her skirt beneath the coat. "If nobody can see it you might as well not have it on". She raised an eyebrow but realised I was right and subtly lifted her coat, undid her skirt and threw it on the back seat.

As we queued for a trolley she got one or two odd looks from the locals, all in shorts and summer tops, but being 30 miles from home meant we didn't care. I made sure to chose some items from the bottom shelves and as she bent to pick them up admired the expanse of bare thigh on show, being sure to stand so that I had the best view and blocked off any chance of her being perved by the locals. I crowded in close behind at the checkout and managed a sneaky feel up her coat, her open crotch knickers giving easy access to her pussy.

Once we were on the road heading home and away from overlooking houses I reached across and undid her coat, playing with her swollen nipples as they emerged from the slits in her bra. She groaned as the thrill of my caresses turned her on and she reclined the seat and spread her legs, stroking her exposed lips and reaching across to rub my tented trousers. The motorway finally appeared and I could risk more distraction, sticking to the middle lane and 70 mph on cruise control. I quickly freed my cock from its' confines and reached over to play with her sopping core.

My ministrations encouraged her to work on me more vigorously, my cock at full attention and leaking pre-cum. Suddenly she threw caution to the wind, squirmed around in her seat to kneel, stretch over the centre console and swallow my throbbing meat. I managed to reach over her back and slide a finger into her wet folds as she worked her mouth over my length. Looking ahead i saw an HGV in the inside lane and as we drew level I slowed to match his speed, knowing he would see her gaping lips as I played with her clit.

The knowledge that she was putting on a show drove me over the edge and I ejaculated just as she reached full depth, going hands free on the steering wheel to hold her head still as I pumped out a full load of cream. She gagged slightly but her own orgasm came quickly and she swallowed everything as her juices coated my hand. Pulling ahead of the lorry I received a flash of the headlights and a thumbs up through the open window. As I swung off at our junction she settled back into her seat and caressed her labia and clit, keeping the tremors rippling through her thighs as her aftershocks came repeatedly.

For the next 15 mins. I had to concentrate on the narrow lanes until we arrived home and could continue our birthday party. We'd anticipated a homecoming like this so our video camera was set up and ready to go in the bedroom. I hit the record button and stripped of quickly as she shed her coat and knelt on the bed, knees wide apart, waiting for me to step up and plunge my rock hard prick into her lubricated canal.. Putting on a show for the camera was the aim and initially I worked a slow rhythm as her juices coated me but eventually excitement got the better of me and spreading her lips wide I pistoned my cock into her until my second eruption left me a weak kneed and slipping to sit on the floor, gasping for air.

She was still on the boil and maintained her pose as she wriggled her arm through her spread-eagled thighs and plunged two fingers into her bubbling fanny, working her clit with her thumb and driving herself to an orgasmic peak for the second time. As she came down from her pleasure plateau and withdrew her hand juices trickled down her thighs.

That's a video we've watched countless times since. Its' titled, "Conception Day". 9 months later a May baby made our family complete, he's grown up and a has a family of his own now but my birthday that year will never be forgotten.