I was watching from the sitting room window when they arrived shortly after two o'clock that Saturday afternoon. I had put our car away and closed the garage door so they had room to park on our drive. They came in a Volkswagen Polo, about seven years old. He held the door politely while she climbed out.
Laura, watching beside me, said, "They look nice enough. Ordinary people."
"That's what they said on the phone. I'll go to the door - we ought to offer them something to drink."
They introduced themselves as Harold and Charmian. He was in a casual jacket and slacks, collar and tie; nothing special but neat and tidy. Charmian wore a dark blue blouse and matching skirt. The blouse was buttoned to the top.
Once they had taken seats on the sofa, I offered to open a bottle of wine. Charmian said they would prefer a cup of tea. "No sugar for me, please, but one for Harold."
"Would you like to have a little chat first?" Harold asked when Laura retired to the kitchen to boil the kettle. "We think it helps the first time. It's a bit off-putting when people want to get down to it almost before you're through the door."
Harold told us he was 34, an accounts clerk for an insurance company in the City. Charmian was 31, an assistant manageress in a shoe shop in Oxford Street. A dozen years younger than us but that didn't seem to be a problem. I said, "You'll need to guide us, I think. How you want to go about it." I tried to sound a little less nervous than I actually was.
"Well, it's not like there are rules. We can do anything you want, but any time someone says no, it means no. After that, we like to play it by ear. Just so everyone can relax and enjoy it."
Charmian touched his arm. "Language, dear. You haven't mentioned language."
Laura overheard this as she returned with their cups of tea. "Is that a problem?"
"No. We just need to know how you feel. Some people are upset by hearing words they already know. It's odd but we can understand it. For ourselves, we think that in the bedroom it's different. Words like 'cock' and 'cunt' add something. We talk a lot." He looked at Laura.
"We have our moments, too," she said. "Let's see how it goes - but don't hold back for us. But while we seem to be clearing the decks, what about condoms?"
I was pleased when Harold gave a straight answer. "We prefer it without - condoms take away something. But it's a matter of trust, isn't it? Some people don't want to take the chance."
Laura and I had talked about this, so I was pleased she had brought it up. We had decided we would make a decision when we saw them. I said, "We wouldn't, either. But if you tell us honestly there isn't a problem, I think we would prefer it without."
One bridge crossed. "Do you usually find the first time easy with new people?" I asked.
"Well, what's usually? It's not as though we are doing this all the time. Only every so often, when we feel the urge for a little bit of excitement. This is the first time for about six weeks. And we need to feel we're with the right kind of people - ordinary, like us"
"But is it usually easy? For people who haven't - well, done this kind of thing before."
"Most times, yes. We try to put people at their ease if they're inexperienced."
"Like us," said Laura.
"I don't think you'll have a problem. We can tell. Sometimes it feels wrong. For instance, when people think we want money. We don't - doing it for money would spoilt it. And we always say no to cameras. Don't want pictures of us in action on the internet. Anything of that sort crops up, we just leave as politely as we can and nothing at all happens."
"But not now?" Laura asked.
Harold smiled. "We'll find out, won't we? The thing is this: have you ever seen people fucking?" He looked at Laura. "Do you mind me putting it like that?"
"No. I've said we don't shock that easily. And anyway, we've seen plenty - pictures, I mean."
"Oh yes, we've all seen it in films - but that's only pretending and clever camera work. DVDs or the Internet are what most people see, of course. But what I meant is - being there while two people are doing it. Close to them. Part of it, almost."
Laura didn't respond. I know her well enough to understand that she was making her mind up once again. I knew she wanted to because she is a very sexy woman but now the moment had arrived, was she ready?
Harold went on, "Isn't that why you've wanted us? To be with us while we do it. You should understand we like being watched. This is what we like to do. Why we are here. It's a turn-on for us, isn't it, dear?
 "Yes," said Charmian. "It can be - well, very exciting. I mean, when we were in the car coming here I said to Harold that we never quite know how it will turn out - me on my back, opening my legs ready to be fucked. And two people we haven't met yet watching us. Just thinking about it made me wet."
And that really was that. Harold looked round our sitting room and smiled. "Where would you like us to do it? We're pretty adaptable."
"Well," said Laura, smiling back. "There's the sofa you're sitting on. But unless you want another cup of tea, wouldn't a bedroom be better? Follow me."
So we took the first step along a very exciting path we had spent a lot of time discussing.
We used the guest bedroom. Laura's father used to sleep there occasionally but since he died there had been no one. This was an opportunity to put it to good use. There's a double bed and we had moved in two small armchairs - for spectators.
"Oh, this is perfect," said Charmian. We'll be fine here."
Harold looked at the chairs and said, "Get as close as you like - this is for you to enjoy as much as us. One thing we don't like is doing it in silence. Don't be afraid to talk to us, tell us if there's something special we could do that would be horny for you."
"Stripping off would be a good start," I suggested.
"Right you are," said Harold. "But can we let Charmian do her party piece first?"
"Party piece?"
"Well," she said, "you know I sell shoes, and I"ve been admiring Laura's May I have a look?"
Having asked my wife to sit in one of the chairs, Charmian knelt down, lifted a foot and removed a shoe. "Very nice," she said, "do you always wear a three-inch heel."
"Not usually around the house but otherwise, yes."
Charmian put the shoe back on and turned to Harold with a smile. "I think you'll be pleased - white ones."
"White -?"
"Laura's knickers. White is a turn-on for Harold."
Laura gave a half-nervous laugh. "How do you know? About mine?"
""It's easy really. You remove the customer's shoe, make a remark and look up into their face for a response. On the way, a practised eye gets a quick glimpse under the skirt. It doesn't always work, but especially in summer with short skirts and a female assistant, women are not always careful about keeping their legs closed."
"It's clever, though," said Harold proudly. "Then she comes home and tells me what she's seen that day, and often that sets us off." Harold look to his wife for approval, and she nodded. "I like white, myself. It always reminds me of our wedding night. We'd fucked before then, of course, but there was something special about Char stepping out of her wedding dress and lying across my lap with her arse in the air in white knickers."
"But not today?" Laura asked with a glance at Charmian's dark stockings.
"No," said Harold, who was already unbuttoning his wife's blouse. "Black today. Sometimes people have a special request - red is a favourite - but we find black is a turn-on most times." He pushed down the zip of her skirt and Charmian posed for us unselfconsciously. Black bra supporting ample breasts, French knickers, suspender belt and stockings. A bit obvious, I suppose, but I liked it. I think I was getting hard.
"Are you a tit man?" Harold asked.
Before I could respond, Laura spoke. "Of course, he is. Aren't all men? I mean - oh, they're gorgeous."
Harold had unclasped the bra and Laura's exclamation matched my thoughts. "You will like these then." He cupped a hand beneath one and lifted it for us to admire the contour. Because these were not conventional round breasts - they were pear-shaped with prominent, dark nipples. Harold bent his head and applied his tongue.
Charmian smiled. "He can do that as long as he likes," she said. "I just love it. The trouble is he can't usually wait to get into my knickers."
As she spoke, a pair of eager hands was already peeling the garment down her thighs before guiding her to the bed. There he asked her to lie on her back and spread her legs for our inspection. She was shaved and the lips were already puffy and I thought they appeared damp. The pale thighs above the black stockings were an almost obscene invitation. I definitely knew I was hard. I wondered about Laura.
As though reading my toughts, Harold said, "There may come a moment when you two may want to stop being voyeurs and join in. We don't always make that offer, but I think you would be OK. If you get the urge, if you know what I mean. Yes, Char?"
"Not a problem for me. But they don't have to."
"Of course not."