I work as a sales assistant in a well known London department store. I normally work in the wedding dress department but yesterday I had to cover in the lingerie department. I am twenty six five feet two inches tall and a size 10 my best asset has always been my bust which measures a generous 38DD without the effects of gravity yet. After the usual lunchtime madness where women come in to buy sexy items of apperall for the benefit of boyfriends or hubbies there is normally an afternoon lull. At this point in came Sandra. Sandra had been 2 years above me at school and was always regarded as the school bike whilst this was a derogatory statement at school secretly all the other girls were jealous me included. Sandra did not recognise me at all, well you only ever remember people in your year or above never below. I asked if she needed help after leaving her to peruse through some skimpy brief and bra sets she said thanks I am looking for a Knock thier socks off outfit. "Their" outfit I said jokingly sounds like find with that Sandra blushed. I had certainly hit a spot dont worry I said I know just the thing and carried on as though I hadnt realised what had just been said. I think you should look at the basque sets if its a killer outfit you want. With that we chose a couple of peach and lemon outfits a virginal white and a fabulous black set. She thanked me for my help and went off to try them on I said take your time the store is very quiet if you need any help just call but i'll leave you alone as there is nothing worse that trying on outfits with the sales assistant hovering just outside. Whilst I went back to tidy through the section I noticed a youngish guy loitering just on the edge of the section I made my way over and asked if he needed any help as a lot of guys are a bit shy at browsing through ladies underwear in stores. "Thank you" he said " but I am waiting for my girlfriend she is just trying some things on in your changing room. Oh you are together I replied maybe you want to give her an opinion. I thought to myself because its being bought to impress more than you isnt it. Off he went to the changing room and I heard her giggle as he went in. I discreetly moved to the edge of the changing area so I could listen properly to what was happening I was really being nosey because I knew her and wanted to pry in her new life pure gossip i know. What I heard shocked me no thats wrong what I heard thrilled me. I heard him say Pete will love that he has no idea how fucking gorgeous you look under your uniform then I remebered somebody telling me she had become a copper. Then I heard the sounds of them kissing and her telling him to stop as she is getting wet and will fuck him right there and then if he doesnt stop. With that I thought to myself in for a penny in for a pound so I put up the Chaning room temporarily closed sign and went into the cubicle next door. Each cubicle only had a curtain in front but were quite spacious with a bench and a full size mirror on the back wall and mirrors to the side. I could hear them getting more and more intense and was desperate to see. I positioned myself so I could peek from the side and see them in their mirror through the gap in their curtain without them seeing me. I saw that by now he had his hands in her panties and was clealry fingering her she was biting his shoulder trying not to make a noise but was clearly enjoying his fingers exploring her. She sat down wearing the peach coloured basque her breasts being pushed high and out making her look like nell gwynn of the modern age she unbuckled his belt and began to suck him right there in the changing room. By now my pussy was aching and I have to admit I was rubbing myself through the material of my skirt. She sucked him for a while and then stood up she straddled her legs open and he bent down trying to insert himself into her but he had his trousers round his ankles and couldnt quite get his balance so she turned round to face the mirror her back to him so he could fuck her from behind with them both standing up. That was it my skirt was up and my hand was inside my knickers I curled two fingers into my pussy and was massaging the front wall of my cunt fast approaching orgasm and I mean fast when.... Sandra looked up into the mirror and saw me. For an instance we both froze our eyes met and then she simply lowered her head back down while her boyfriend who who totally oblivious to this carried on fucking her for all he was worth. About 30 seconds later he announced he was coming she quickly turned around sat back on the changing bench and let him come all over her pushed up breasts, They were absolutly covered in his cream I have never seen a man cum that much not even on a porno movie. She pulled down the front and massaged some of it into her very erect nipples. He suddenly came to his senses as only men do and instaed of being the gentleman to help finish her needs off he pulled up his trousers and announced he would wait outside in case the shop assistant became suspicous. I hid behind the curtain as he left the area and then went in to see how she was getting on. She was still sitting there covered in all that jizz and said I was hoping you would help with the fitting. At that she leant back and started playing with her pussy she put two fingers inside herslf and then offered them up to me to lick I willingly licked and sucked them clean and as I did so she pulled my panties to one side and began to finger me. I quickly slipped them off and proceed to give a a major french kiss swapping tongues greedily and readily I had only ever had one girl on girl encounter which was a 2 minute fumble but this.. this was heaven and soooo naughty. I started kissing her neck and then moved down to her spunk coated breates I'd always been partial to fresh virile semen. I licked and slurped at her nipples sucking every last drop form them and then and then I kept going down to her pussy. sandra lent back opened her legs as wide as they would go and with me kneeling on the floor let me lick her to oblivion 30seconds later she was quite literally squirting pussy juice all over me some of my friends had said they squirt but I didnt really know what they meant now I do. Sandra said your turn she quickly changed places with me now I was sitting on the bench my skirt hitched up and with this "customer" licking at my pussy. I caught sight of myself in the side mirror I looked like a real dirty slut skirt up blouse with spunk stains and pussy juice all over where i'd leant across her to kiss. I hitched my blouse out of the skirt pulled it up and released my breasts from their prison. I pulled on my only nipples and looked in the mirror again for as long as I could and then then I closed my eyes and could feel wave after wave go right through me as she fingered my arse and licked my pussy i was pulling my nipples so hard i'm surprised they didnt come off. Well she said I'm not sure I can buy this out fit it appears to be marked no problem madam said I dressing as we spoke and pulling my blazer closed covering the soiled blouse "I'll return it to the rail and find a fresh one". She came to the cash desk a little bit later she had a real cheeky knowing look and as her boyfriend came alongside he looked really sheepish as though I knew what they had been doing..if only he knew or maybe by now he does. Anyhow I have asked for a transfer to lingerie full time so if any ladies need some help in choice the right outfit dont hestitate to as!!