I am sitting in Anna's luxurious suite, while she talks with her agent in the US. I gather that he urgently requires her to fly to NY for a photo-shoot, and has booked a first-class flight for her from Heathrow this very evening. I find the demands on her somewhat unreasonable, but it is the life she chooses to lead.

While this is going on, I am increasingly worried by Sara's message. It seems she has been trying to contact me all morning, but gets no response from my room, and is now very concerned.

Anna rings off and begins to pack frantically. She suggests that I should use the remaining day's booking of the suite and assures me that all expenses will be settled by her agent, when I leave on Monday.

I am a little unsure, but then she says, “Why don't you just invite Sara round now, and use the suite as you wish? I will explain everything to her.”

That doesn't reassure me much, because I think Sara will be upset to find that I have been with Anna all this time, and Anna will not be subtle in her explanations. Even so, I don't see any alternative, and I message Sara to come to Anna's suite.

I intend to be honest with her. It is only because of Anna's comments that I now understand that Sara would like our friendship to become much closer. She has never made that clear herself, but I do recall that she warned me of Anna's reputation and hustled me out of the room yesterday. I had thought, at the time, that she was simply being protective of a naïve friend, but perhaps there was more to it than that?

Anyway, there is soon a loud knock at the door, and as Anna continues to pack, I open the door to Sara. She bustles in, looking very agitated, and squares up to me.

“What is going on, Simon?” she says, and seems extremely cross with me.

I say that I spent the night here at Anna's invitation, and Sara sits dejectedly, staring at me. “How could you?” she says, “After I warned you about Anna!”

I sit alongside her, and say that I don't understand why she is quite so annoyed.

“I know that Anna is your friend, but it was Anna who invited me here, and her who seduced me, not vice versa! I didn't seek her out, and you know very well that she can make herself irresistible to any man.”

At this point, Anna enters the room, and backs up what she has overheard me say.

She tries to placate Sara by telling her that she has only just revealed to me that Sara wants our relationship to be closer, and that if she herself had said so earlier, I might have resisted Anna!

To be honest, I am not sure that is true, but Sara says, “God, I am so confused now! You mean you have seduced and fucked Simon, but told him that I want to be closer to him? That was something I said in confidence to you! You had no right.”

“Well,” says Anna, “the only way is to be honest and open, Sara. I'm handing over the suite to you and Simon for the night, so you need to talk honestly together and get your relationship clearer. I'm very clear that what he and I had was just sex, nothing more. And by the way, Simon is a great fuck!”

Anna takes Sara aside to talk more privately in quiet tones, and I simply sit and observe them as their manner towards each other seems to soften.

They are both beautiful women; Anna is a little younger than Sara, and I had thought myself too old for both. They are both very slim and fit, as dancers, though Anna has achieved more fame and fortune. Anna has long golden-blonde hair which cascades down her back, contrasting with Sara's shoulder-length, raven-black hair.

After our recent trysts, of course, I know all the intimate details of Anna's body, but I only recall seeing Sara in a bikini once or twice. I get the impression that her breasts are a little larger than Anna's, but otherwise, both are tall, slim and long-legged, and both carry themselves elegantly. They are also both intelligent, strong women.

The two of them seem to have made peace, and they hug tight together. It must be an optical illusion of some sort, but as they hug, backlit by the low autumn sunshine, it seems to me that they almost merge into one person in front of me.

Then they part and Sara seems to have a new glint in her eyes, which reminds me of Anna. Their friendship is obviously very close, though not sexual, and I now see something of Anna in Sara, though moderated compared to Anna's 'full-on' sexual persona.

After their private conversation, Sara seems more self-assured than usual, and certainly more composed than when she arrived at the door a short while ago.

Now it is time for Anna to leave for Heathrow. Her bags are collected, and she orders lunch to be delivered to us in the room.

As she leaves, she hugs me too, and her hand presses against my cock. “Bye, lover,” she says, and turns to ask Sara to “tell her all about it” later. Finally, we are left alone together in awkward silence, in a luxurious suite, with lunch on the way, and all expenses paid.

We have been friends for a long time – years rather than months – and we have talked a lot about everything under the sun, except the nature of our own relationship.

We often discuss politics, philosophy, and religion; art, music and dance; morality, sex and porn. We either agree, or at least we understand each other's views, in all these fields and many more. But we have never talked about our personal sex lives, except flippantly and in passing; it has been a hidden aspect. Now is the time to address this failing, so we can move forward.

We each know that the other has had several partners, over time; some were entered into in the belief that a long-term relationship might develop, some (like mine with Anna) were “just sex”. Neither of us is sexually inexperienced, but why have we never considered each other as sexual partners?

The only explanation we can give is that neither of us wanted even to risk losing the relationship we had developed as friends, if having sex might jeopardise it. There was clearly a risk of that, though Anna's opinion seems to be that we would succeed – and she is an experienced judge.

So, over lunch, we discuss our own personal sex lives openly for the very first time.

Sara starts boldly by asking whether I have ever thought of her when I masturbate – she rightly assumes that I do. I have to admit that I had, and ask her the same question.

She admits that she has a 'bullet' vibe, no bigger than a lipstick, which she carries in her handbag; more surprisingly, perhaps, she says that she calls it 'Simon'. I am truly astonished, but flattered.

These revelations lead to more, and more. Maybe the wine accompanying our lunch helps a little too.

We agree that neither of us wants to give or suffer pain or humiliation; BDSM is not for us. We want an equal sexual relationship, even if one or the other might dominate on a particular occasion; we both value spontaneity.

We both love oral sex, whether giving or receiving, but we both broadly reject the idea of anal sex, despite its popularisation through porn sites. Perhaps we might be persuaded, but...

We are happy about different positions on different occasions; we both like the doggie position, for “just sex”, but prefer missionary for more “loving” sex. Neither of us know why this is regarded disparagingly as 'vanilla' sex, when it seems to be the most common position for loving couples, though we do agree that it should not become the only position ever adopted – there are so many more to enjoy, after all!

Now we agree to undress and explore each other. We have seen each other on the beach, for example, but never wholly naked and certainly not detailed investigation.

Lunch is finished and set aside, and we stand in front of each other. We undress each other simultaneously, but slowly and carefully, appreciating each revelation.

I find Sara's breasts a little larger than I had assumed, when I remove her prim blouse. Her areolae are pink and widespread, compared to Anna's darker, smaller nipples, but Sara's nipples themselves are extraordinarily long- she is already aroused but they are remarkably firm and outstanding at the points of her breasts.

Her hair is shoulder-length, raven-black, and glossy; when I run my hands down her slender but shapely body and remove her panties, I see that her pubic hair is equally luscious, black and glossy, but carefully cut into a short triangle, pointing very clearly down towards her pussy.

Her pussy is tucked away between her legs, and her lips are more hidden than Anna's very prominent and completely bare pussy. I think her clit is hidden too, but I have yet to touch her, of course. I tell her that she is beautiful, from every aspect.

Sara undresses me at the same time, stroking my naturally hairless chest and down to the short-trimmed hair around my cock and balls. When my erect cock is revealed – how could it be otherwise? – she murmurs that I am a little larger than she had expected, and comments on the thickness too.

In summary, a very “strong” cock she thinks, with balls clutched tightly beneath. At least I seem to meet with her approval!

We agree that we would each like to explore in more detail, and the best way to do that is through oral sex, in the 69 position. We retreat to Anna's bedroom, and stretch out together on the comfortable bed, which I am already familiar with.

I explain that, though I love the 69 position, I find it impossible to concentrate on my own role, if my partner is busily playing with me; it can become a distraction, to say the least. So we agree to take it in turns, and I will begin.

I part Sara's thighs and stroke gently and slowly inside her legs from the knee up to her pussy. She breathes steadily and calmly, allowing me to do whatever I wish to her body, while she relaxes completely.

I stroke her more and more firmly, pressing my thumbs into her muscular dancer's thighs, like a deep massage. She loosens her tight muscles, and my hands move to explore her pussy, where the tight, wrinkled lips are slowly starting to puff up and open of their own accord. She is so very different to Anna, but I have always found pussy fascinating in its variety.

I part her outer lips, and run my fingers along the full length, spreading her slickness towards her hidden clit. It does not take much doing to draw back the hood and reveal her swelling clit. It remains prominent now, and open to my mouth to suck, lick and nibble, while my fingers can probe between her lips and inside her vagina.

First one finger, then two, pressing and curling upwards inside her, while I play with her clit, She is moving against my mouth, and against my fingers now, clutching at them with her vaginal muscles. I move in sync with her, increasing the pace of my fingers as she presses herself more firmly against my mouth with accelerating rhythm.

It is clear that she is approaching her orgasm, and I let her use my mouth and fingers as she wishes. Her breathing gathers pace and depth, until she is gasping for breath, and begins to growl deep inside her chest.

The sound swells until it bursts out in full volume, and changes to loud cursing, while her body trembles, her pussy lips flutter in front of my eyes, and her muscles grip rhythmically around my fingers. At the same time, she grips my cock very tightly, almost painfully so, and distracts me a little from my task.

Slowly, the pulses subside and her breathing slows too, until she is calm and relaxed, her body softening and allowing me to withdraw my fingers from her dripping pussy.

She says, “ My God, Simon, Anna was right. Why haven't we done this before?!”

Before I can even attempt to form an answer, she has taken my hard, throbbing cock into her mouth, and is swirling her tongue around the head while stroking the shaft with one hand and teasing my balls with the other. I feel her tongue, teeth and inside cheeks all brought into play, and her lips grip tightly around me when she sucks noisily, and forcefully, on my cock.

I think she knows that I will cum soon, and just as I had, she increases the pace and depth of our engagement. I lie back now, and let her do as she pleases; I know I am enjoying her attentions.

After a few more strokes, I just have to thrust myself through her wet hands again and again, and she grips my balls more tightly. The time has cum too, and I shoot spurt after spurt into her mouth, while she grips tightly around the base of my cock. I'm sure she can feel the pulses through her hands and certainly into her mouth, which fills rapidly; I'm not sure whether she can feel the twitching of my balls as they empty themselves into her.

She takes one great, noisy gulp and withdraws my cock from between her lips, allowing some cum to leak over them. A little dribbles slowly down her chin as she smiles widely at me, then licks her lips.

“Like I said, Simon, why haven't we done this before?” she asks again, and giggles.

“I really don't know!” I say, “but I think we'll be doing it again.”

And so we do. After a pause for showers and recovery, a dinner is delivered to the room, during which we discuss how to proceed.

Our conclusion is that we should have our very first full penetrative sex in the missionary position, and maximise the potential for slow, loving intercourse. We want to know whether we feel emotional “love” between us, rather than “just sex.”

We stand naked before each other, and stroke each other's body gently, slowly and cautiously. This alone has the obvious visible effect on me, but Sara also tells me that she is beginning to feel wet again.

We hug together tightly, still standing, and my erect cock presses against her flat belly. She is a little shorter than me, so when we hug, I am looking down into her upturned face, and it is natural for us to kiss now. We do so at great length, using lips and tongues vigorously, mixing saliva without a thought, and looking deeply into each other's eyes. It is a delicious few minutes of exploration.

It is both arousing and gently comforting to take our time like this. The feelings we are experiencing are certainly as much emotional as they are sexual, but we need to progress to full sex.

We have agreed on face-to-face missionary sex, so Sara simply shuffles backwards into the bedroom, and I guide us towards the large bed I had shared with Anna the previous night.

When we reach it, she topples backwards and I fall softly on top of her. We both have to wriggle up the bed a little, and in doing so, my cock makes its presence felt between her legs.

I lift myself up above her to remove some of my weight, but she pulls me back down to press my chest tightly against her soft breasts, and squirms slightly beneath me, as though she is trying to get even closer.

Without any effort at all, we do naturally 'become one' as my cock slips easily into her slick pussy, and she wraps her strong dancer's legs around my hips. I penetrate her slowly and as deeply as possible, and for a while, we simply lie locked together while we continue to kiss, not only on and between the lips, but all around each other's faces – cheeks, chin, nose, eyes, forehead, ears and neck. Anything within reach! She jumps with shock when my tongue-tip finds its way into her ear, and pulls away.

I press back against her restraining legs, to withdraw from her, then allow her to slowly pull me back inside herself. With remarkable restraint, we complete this manoeuvre several times, before a lusty urgency takes hold and we both begin to move more quickly, banging harder and harder against each other as the tension builds inside both of us.

Inevitably, we reach a climax which has us both shaking with the release of the pressures we have built. We lie still together, my cock locked inside her spasming pussy, while I fill her full with spurt after spurt of hot cum.

When the pressure subsides, we remain in position for a long time, just enjoying the warmth of each other's bodies, and the dampness we have created between us – we are both exhausted!

I withdraw my softening cock and roll aside, unsticking our bodies, which were glued together by sweat and our juices. We lie alongside each other and agree that was NOT 'just sex', but a much closer connection than that. Whether it is “love”, only time will tell, but we are both keen to keep testing the theory – it was certainly a more emotionally complex experience than either of us had had before.

“If that is 'vanilla' sex, I'm all in favour,” I say. “I've always preferred vanilla ice cream to chocolate, anyway!”

“I agree,” says Sara, “that was a great experience. But perhaps when we recover, we can test 'just sex' as well? We do have to make SURE, don't we!”

I think we need to sleep now, so we cuddle together and doze off until the morning.

When morning breaks, we know we only have Anna's suite until midday, so we order breakfast in the room, and it is delivered while we shower. After breakfast, we move the remnants outside the door to be collected, and hang the 'Do Not Disturb' sign on the handle.

Now we have the morning to ourselves, with no fear of interruption.

We remember that we both agreed on the 'doggie' position as a favourite, especially for 'just sex'. There is obviously no face-to-face connection, but it does allow for the deepest possible penetration, which we will both enjoy.

In a partial compromise, I realise that there is a large mirror in the wardrobe alongside the bed, and I suggest that Sara should kneel facing it.

In preparation for the 'main event', I approach her from behind, but lying flat under her, and worm my way up to position my head between her legs. She is a little surprised by this unscripted approach, but she is not going to refuse my oral attentions again, to prepare her for an animal fuck.

So, I probe her pussy again, parting the lips above me with my fingertips, and delving between them with my tongue. I lick upwards to her clit, and she begins to drip honey in anticipation of what is to come.

She cannot resist moving back and forth above me, in dancing hip-movements reminiscent of Anna, and begins to press herself down onto my mouth more and more forcefully.

I do not want us to get too carried away in this position and I judge that she is now ready for fucking as we had agreed, so I slip out from under her, and spin into position behind her.

She realises what is about to happen now, and drops her shoulders low onto the bed, her head on one side, her ass raised. I approach her and admire the shapely ass in front of me, simply begging to be fucked.

I look ahead and see myself in the mirror beyond the bed, over Sara's body. She looks up too and sees herself with me behind her, and we make eye contact in the mirror. It is a great feeling, and we try to maintain eye contact in this way, while I slowly slide my hard cock into her wet, welcoming pussy.

When I am fully embedded inside her, holding her hips against me, we smile at each other. But when I slowly withdraw, then ram hard and deep into her, she gasps with the shock, and her eyes widen.

This becomes a regular rhythm of slow withdrawal followed by sudden, deep thrusts, increasing steadily in pace. I break eye contact to look down and see my own glistening cock sliding smoothly into Sara's pussy; that is always such a delight to see. I think she realises, because when I look up again, she is smiling back at me, between gasps of shock with every thrust.

She begins to move in response now, and we forget about the mirror. Our focus now is on satisfying our own primal urges. As I thrust into her, and she thrusts back against me, the momentum becomes unstoppable and our grunts and moans become louder and louder.

Finally, Sara screams and her body shivers, while I give one final thrust and pump yet more cum inside her.

I withdraw and cum gushes from her, mixed with her own juices, as we fall apart and roll into position alongside each other.

"Just sex, eh" says Sara, "It didn't feel like it to me!"

I agree, of course, but I think there was a definite difference to the previous missionary fuck; this was not devoid of emotional connection, but it was definitely more 'animal' in every other way.

Now we have to shower yet again, and compose ourselves, ready to leave the suite. As we are making final preparations, Sara's mobile rings. She looks at it, and then at me. "It's Anna," she says, "She must be in New York now! I will have to answer her."

Of course she does, and puts the call on speaker, so that I can hear clearly too.

Anna asks whether Sara has enjoyed the day, and her time with me. "He was a great fuck," Anna says, " I hope you had fun together."

Sara chuckles at Anna's blunt forthrightness, but smiles at me as she agrees with her appraisal of me. Their conversation suggests that Anna may not return to London for months, certainly, and possibly for years. She hopes that Sara will forgive her for seducing me, and that the two of them can continue to chat online.

I listen with interest as Anna seems to suggest that she is finding non-committal 'just sex' a rather empty experience now. She enjoys it, of course, but like Sara, feels that she now wants a deeper, more committed relationship, which has a real emotional content too.

Sara says, "I think I may have found that with Simon, Anna. It is probably because you seduced him that this has all come about now. We could have gone on for years being 'just friends', but now we have at least added some 'benefits'."

Looking at me, she says to Anna, "I hope we can become an 'item', not just friends."

Anna says she is delighted for us, and hopes that she will be able to develop a similar relationship. Apparently, there is someone in the US who she has strong feelings for, not only sexual, but as a friend and confidant who she can really trust.

They agree to keep chatting online and sharing their thoughts, and Sara rings off.

As we pack up to leave from this extraordinary weekend, I agree that private online chatter between them will be perfectly acceptable. Their 'girl talk' may include references to me, as I have fucked them both, but Sara is adamant that Anna will never seduce me again.

Her final words, as we leave the suite, are "If Anna ever comes to London again, Simon, I will even trust you to be alone with her."

I'm not sure that is wise, but it does confirm her faith in our own relationship.

It has been the most significant weekend in both our lives, so far.