Young ladies are smart. They are clever, deceitful, underhand and, at times, malevolent. They are also good fun, sexy and damn delightful when they want to be. Take the two young girls who work in our office – they are the "bestest" friends and share a flat, but they are always up to something. The other day I got tricked into buying biscuits for the office when it was Sandy's turn to furnish our bird table with cakes and treats.

She flashed her grateful smile at me, as she adjusted her dress in the impossibly warm office, and a lump formed in my trousers. I loved her cute smile, and incredibly toned body, as well as her giggly expressions; she was wonderful, and manipulative.

Belle, was even more obvious with her charms. The 5ft 6in petite minx was always asking some of the more malleable of men in the office to rub "moisturiser" or sun cream into parts of her body, happily lying on the couch in the canteen as a naïve trainee succumbed to her charms and massaged her bare back. She was also incredibly playful and got involved in a Super Soaker water fight at our Team Building weekend at Easter, while dressed in white clothing. It became rather obvious she was not wearing a bra!

The love lives of the two girls was a subject that was discussed between them every week in loud voices. Sandy's long-term relationship had reached a messy conclusion when she caught him in bed with another man, while Belle had had a hundred transient couplings over the year. She always denied she wanted to settle down, which I could almost believe; from the tales of her Saturday nights, I doubt many men could keep pace with the rampant nymphomaniac even if she wanted to.

The girls brightened the office considerably, and the dour nature of our work was made tolerable by the gleeful smiles and bounciness of our two young ladies. They were also very good at their job, and competed good-naturedly with each other. Sandy even gave Belle ten "spanks" after a small accountancy error, which caused the office to stop and watch open-mouthed as the girls toyed with the men. There were a fair number of trips to the toilet for "number threes" shortly after their little show!

Last week, I was talking in our small work's canteen, when Sandy overheard me saying that I was planning to go to the local National Trust park at the weekend for a picnic, and she invited herself and Belle along to my quiet time. I didn't object – I didn't want to know what rumours would be muttered if, as a single man, I rejected the company of two beautiful ladies – and met them outside the gates of the park the following Saturday laden with a heavy picnic bag.

Sandy had been very specific with an email on the Friday. I should bring sandwiches of three flavours, crisps, juice, cakes, chocolate, wine, pork pies, plates and plastic glasses. She signed her email with several "X"s and blew me a kiss when I looked across the office at her; I had butterflies for a moment.

I didn't think of it as a date, but it was a beautiful day and had chosen shorts and a T-Shirt to wear. Sandy was wearing a brightly coloured summer dress that stopped at her thigh, and Belle's blue outfit finished somewhere between her upper thigh and her paradise! They grinned at me ogling them, but Sandy adjusted her large summer hat and pouted teasingly. "Will we do?"

An understatement if ever I had heard of one! They looked divine and so sexy. I stammered in response, but the two girls took an arm each as we walked into the forest. I got a couple of envious looks, but why shouldn't I? I felt like "the man!"

The two girls were in a playful mood; I was teased by them relentlessly, but it was in good spirits and I did get to hear about their last weekend in graphic detail. I had always thought of them as being quite sexually liberated by their chatter in the office, but I only knew a fraction of what they got up to: I certainly had a sexual education.

The walk through the forest and down the hill was lovely. Although it was a warm day and the car park was busy, most of the visitors followed the set walks around the park, and never ventured too far from their vehicle. By the time we reached the bottom of the hill, we were at a small exit to the park, but had not seen another living soul for almost half-an-hour.

We turned around, but Sandy tugged at my arm, and pulled me towards a break in the trees, that lead into a small meadow, surrounded by tree-covered steep slopes and bracken. "Here'll do," she announced proudly, and the little tease flashed her smile at me. I couldn't resist smiling in return, and she guided us to the corner of the "meadow" as it wasn't in shade and sat down; I think she may have been here before!

The two ladies and I devoured the prepared picnic; I got a kiss on the cheek from both of the minxes as a "thank you" and Belle lay on the ground, staring at the cloudless sky. "I love Britain in this weather," she mused, not straightening her dress and allowing me to see her bright pink thong that barely covered her inviting pussy underneath.

I know she grinned when she saw my eyes flicker towards her slightly splayed legs, and I looked away, more in embarrassment and shame than anything else. Belle oozed sex: every movement she made was enticing and arousing, and every glance radiated decadence and lust. She gave me a raging erection and I looked towards Sandy finishing the bottle of wine.

"We could do a bit of sunbathing," she suggested, looking at me. "Our flat doesn't have much sun." I bit my lip; if I had known the girls were going to lie in the sun I would have brought my book, but Sandy must have read my mind as she putted her hand on my bare knee. "If you don't mind?"

"Errr ... no," I muttered before I thought, gazing into her pleading eyes. She thanked me, by patronisingly patting me on the thigh and put the last of her rubbish in the picnic bag, before turning away from me. I wondered about stretching my legs for an hour while Sandy and Belle improved their tan, but was distracted: Sandy slipped out of her dress.

I gasped at Sandy, dressed only in walking boots and pastel coloured underwear. The black-haired girl giggled and looked at Belle before blowing me a kiss. She kicked off her chunky footwear and dropped her bra onto her clothes, releasing a perfect pair of breasts to my fortunate eyes. "What?"

"You're naked!" I cried but Sandy didn't flinch.

"No, I'm not," she replied and lay down in the middle of the meadow, next to Belle, facing the sky. Her pert breasts pointed towards the Sun and the lump in my trousers doubled in size! Her friend cackled and sat up.

"If you don't want to look at her, you can give me a massage," she offered. Once again, she flashed the trademark smile: warm and enticing, irresistible and disarming; I was putty in their hands. She too, turned away and removed her dress and bra, before lying topless on the soft grassy carpet, face down next to her friend.

I hesitated; I had no idea what she expected but Belle guided me through her massage, telling me to make lazy circles on her skin and press down gently. My clammy hands trembled on her lightly tanned flesh, and Belle passed me some sun lotion for me to apply to her back. It made the "massage" easier: my hands had less resistance as Sandy drifted off to a gentle snooze.

The soothing sounds of Gaia – the tweeting of bird song combined with the soft psithurism of the breeze – provided a delightful atmosphere to my novice massage. Belle purred, her shoulders relaxed into the soft ground as my hands reached her rump. "Take them off," she muttered to me, as my hands touched her neon pink thong. I saw her lips curl upwards as I stammered. "I don't want sun cream on them."

For a split second, it seemed like such an innocent request and the young lady made me wipe my hands on the grass before touching her underwear. Butterflies danced in my stomach for a second as I gently tugged her underwear to her ankles, and then placed them on the grass next to her. I tried hard not to look at her pussy lips, poking enticingly from between her thighs, but my cock implored me to look and my eyes shamelessly lingered.

Belle knew what she was doing and she asked me to massage her rump as "it gets sat on all week." I think Sandy giggled as I did; my hands shaking and my body squirming as I touched her peachy bum, squeezing it gently in my hand.

She laughed, and I removed my hand, but I was gently chastised for my reticence and Belle parted her legs slightly "to give me easier access." I wondered how far Belle would go, or let me go, but she remained unfazed as my hands slipped between her thighs.

She looked over her shoulder at me, and licked her lips. I was swimming in arousal, desperate to touch this beauty and guided my hand over her cunt, winking seductively at me in the Summer sun. She sighed as she exhaled, and parted her legs further, inviting my hand into her heavenly crevice. She wriggled and pushed her waist further away from the ground as my fingers delved between her body and the soft green carpet.

I found a welcoming, slippery wetness gliding over the tips of my exploring fingers. She sighed loudly, enjoying my blatant fingering. No longer was I pretending to massage her rump, but was brazenly touching her moist delights in public. I watched her expression, eager to see her approval etched upon it.

She buried her face into the grass as my fingers touched upon her clit, poking out from underneath it's hood. Her body shivered as I rotated her pearl around my finger. She was clearly on heat and highly aroused, pushing her breasts into the soft grass and parting her legs wider. She groaned as my fingers touched her hole, sliding effortlessly into the well lubricated woman, causing her to gasp with excitement and anticipation.