The Swap
Chapter 1

Caution: This Sex Story contains strong sexual content, including Ma/Fa, Fa/Fa, Mult, Consensual, Romantic, BiSexual, Heterosexual, Cheating, Swinging, Group Sex, Oral Sex, Masturbation, Voyeurism, Slow,

Desc: Sex Story: Chapter 1 - Twin brothers, and their respective spouses come up with an old solution to an old problem.

We were both lying on the deck in the hot sun together, naked if you please. My friends would never have believed it. I'm normally very shy. Well, I used to be.

Erin was gorgeous, no doubt about it. Her tall slim body was tanned and topped with long blonde hair, and her slight face carried one of the sweetest smiles around. Her breasts were large but firm, and also tanned. Her not-so-private parts were decorated with hair of the same pale blonde, a stark contrast to the rich tan covering her whole body. No chance of shyness from this one.

How could I compare with a living doll like that? Well, I couldn't, but I wasn't too bad looking just the same. We were a study in contrasts. I was slightly younger at twenty eight, somewhat shorter (alright, quite a bit shorter), and my hair was black, upstairs and down. My breasts were smaller, but Mark insisted they were just perfect. I was also missing the whole-body tan.

I was sporting the ever popular pale fake bikini look. We had been on the boat for about two weeks now, and Erin had slowly convinced me to wear less, so my standard shirt and shorts had progressed down to a skimpy two-piece, and then over the last few days I had worked up enough courage to remove the bikini top, and finally the bottom. The result was that I was well tanned in some places, and a stark white in others. My breasts, buttocks and other parts had never seen the sun before. I wondered how they were coping, and tried not to stay in the sun too long.

Nonetheless, I was relaxing into the idea. After all, there were only the four of us on board. Erin's husband Matthew was very much the gentleman, and I was married to his slightly younger twin brother Mark, so it's not like I was out there showing off to strangers. Oh, I'm Holly. Forgot to tell you.

Matthew and Mark had done the right thing and left it to Erin to arrange nudity at her own pace, and then they had appeared on deck yesterday with their family jewels on display for the first time. Of course, I'd seen Mark's equipment before, but I'd always been interested in comparing them. I mean, I'd heard that identical twins were, well you know, identical, but it's not the same as seeing it for yourself. And they weren't. Matthew's looked slightly larger from where I was.

His equipment had come up in discussions before this trip as well. He and Erin had been trying to have a baby, and whilst they had very much enjoyed the practice, they didn't seem to be able to get anything started, so they had both gone in for tests to see what the problem was. Turned out that Matthew's sperm count was lower than my financial worth. That's depressingly close to zero. The baby project had gone on hold for a while to consider options, and I had insisted that Mark have himself tested as well, in case it was some genetic problem. Mark passed with flying colours though, so I breathed a huge sigh of relief. We had no immediate plans for parenthood, but I had plotted out something for the long term, and he featured in the starring role.

As we lay there in the still heat, cold drinks beside us, elbows on pillows, and the unmatched sets of buttocks in the air, Erin and I chatted about anything and everything. The two of us had become close friends over the couple over years since we had met. We both felt comfortable on most any subject.

Erin had seemed a little quiet today though, as though she had something to say, but didn't know how. I just waited. She would tell me when she was ready. And that turned out to be just after lunch, as she browned her behind, and I burnt mine.

"Holly, I want to ask you something, and I'm worried what your reaction might be."

"Oh, come on. You've asked me some real curly stuff. Hell, you know more about me than Mark does. By the way, I hope you're not blabbing any of that history to Matthew."

"Oh, no, anything we say stays between us. I promise. In fact, given what you just said, maybe I should just tell you straight."

"Of course you should. Come on, get with it."

"Okay." Nonetheless, she paused here for a breath, and then proceeded, speaking quietly and precisely, not at all her normal style. "Well Holly, I want a favour from you actually. You and Mark."

"You name it, I'll consider it. Come on, how tough can it be?"

"Well, you know this trouble with Matthew's sperm count?"

"Of course."

"Well, we have discussed it, and decided that we want to try a sperm donation. And we'd like the donor to be Mark."

"You would? Well, I can't speak for Mark, but I imagine that would be an honour. We discussed this possibility, and I'm pretty sure he'll say yes."

"He will? That's great. There's just one other thing though."

"What's that?"

"Well, we also decided that we didn't much like the idea of all those test tubes and doctors and labs and stuff. We thought the best way would be the old-fashioned way."

"Old-fashioned? What do you mean?"

"You know, the way most people make babies."

"You what? Sorry, I've got that wrong. It sounded like you mean you want have sex with him."

"Well, actually, that's what I meant."

"What! You want to fuck my husband?"

"I wouldn't have put it like that, but essentially that's correct. I want to borrow Mark for stud services. After all, he's the closest thing to Matthew, genetically speaking. No one ever needs to know."

"You lie here beside me, and want to borrow my husband? Jesus Erin, you've got balls, haven't you? How do you think he'll feel about all this?"

"Actually, he and Matt have talked about it already. He's willing, but only if it's alright with you."

"He's... talked... willing..." And at that point I stood up and walked away. I was so shocked I couldn't bring myself to speak about it. Desperately needing some space to think, I walked down the stairs, and into the cabin Mark and I were using. Erin was calling to me from the deck, but I didn't take any notice.

I stayed in the cabin for a couple of hours, thinking over what she had said, and how I really felt about it. I went through the full range of emotions, and finally decided that I was neither disgusted nor frightened, though I thought I should be. Instead I was intrigued. Mulling over the options further in my head, I realised that I could live with this, but only because I liked and trusted all three of them so much.

Clearing my head, I returned to the deck, to find my three naked companions standing around sipping wine. The sun was still out in force, and the heat outside was intense, but I was struck first by the way they were all standing watching the hatch, and waiting for me to reappear.

"Guys, I'm not going to discuss this with all of you, so you can just stop with the staring."

Erin recovered first. "We weren't staring Holly. We're worried, and trying to work out how to help."

"Well thanks Erin, but I don't need help. I need my husband. Mark, can you take some time out of that sun, and come talk to me?"

"You bet Hols. Guys, we'll be back in a while. You sure you're okay?"

"I'm fine Mark. Really guys, I am. Just give me a while, huh?"

I disappeared through the hatch again, a private smile on my face. I could hear Mark following behind me, and turned into the cabin without stopping to look. Once I was inside, I sat on the side of the bed, and looked up at him as he appeared in the doorway.

"Sit down Mark. Here."

"Listen Holly, just say no. There won't be any hard feelings, I'm sure. They can just..."

"Shut up and sit."

He did. He just sat there and looked at me. God, he was beautiful. I turned to him, stood, parted his knees to give myself room to stand properly, and presented my right breast to him, just in front of his mouth, smiling at the stunned look on his face.

"Shh. Suck while I talk. That's better. Listen, I've been thinking about Erin's proposal, and I want to tell you about that, but I don't want you to say anything until I've finished, understand? Ooh, careful with the nodding. That thing's delicate. You are really good at that, you know?"

"Okay, listen up. I'm willing to go ahead, and let you fuck Erin. No need for the eye popping. 'Fuck' is the correct word, I hope. Because listen to me, if it's more than that, if you have feelings for her you haven't mentioned, you better bring it up now. That's a shake of the head, is it? So fucking it is? Okay. God, could you do the other one? Mmmmm..."

"It's okay for you to be attracted to her. You can want to get into her pants. I'm fine with that. But I'm assuming you have no plans to take her away from Matt? Good. Ooh, I have a confession. Talking with you about this is so hot. You think you could make use of that hand, down here? Yeah, like that."

"But there is a condition, husband of mine. Oh, look at that. I'm not the only one this excites. You want to talk about that some more? You like it when I discuss you fucking Erin? I bet you want to put your cock in her real bad, don't you? You dirty bastard, look at it quivering. Here, lemme help with that. Don't stop what you are doing though. Oh, that's good. You want to make her scream Mark? You want her pussy dripping wet and begging for it? You want to slide your fingernails across her ass, slip your fingers in beneath her blonde hair? Ooh God, keep doing that lover. Just a little faster honey. Oh!"

I came, standing in front of my husband, his lips and tongue tormenting my nipples while his fingers dug deep inside me as only they know how. His thumb hovered over my clit, applying perfect pressure, perfect timing.

Pulling away from his mouth for a minute, I realised I wanted him in me. I wanted to feel him come, to take his seed from him before I let him go. I realised I still hadn't told him the condition.

"Shuffle back a little, honey, I want to get that inside me before it explodes. No, don't lie down. Just site there."

"God Holly, what in hell..."

"Shut up and fuck Mark. Just because I took my mouth away, doesn't mean you can start talking. Anyway, I still need to say something to you."

I climbed up on the bed, on my knees, and knelt there, my breasts in his face, my hands wandering, both aimless and desperate. Slowly I lowered myself toward his waiting cock, shuffling my knees forward. It all felt a little awkward for a start, but when I looked up at his face, I knew he had no complaints.

I stopped when I felt the pressure of his erection on my labia, pulled his head down hard, and latched our mouths together. As my tongue plundered the inside of his mouth, preventing us both from speaking, I manoeuvred a little further down, and his cock slid, slowly, but firmly, along the line of my labia. I could feel the solidity of him against me, but the pressure was just enough to move his hardness where I wanted it.

As the very tip of his penis slid far enough, it touched my swollen clitoris softly, and I surprised myself by coming again. An almost painful series of contractions racked my carefully placed body, sending waves of pleasure through me. The intensity was too much to last for long, and I soon collapsed in toward Mark, my mouth falling limply from his, my labia parting and allowing him to enter finally.

Sinking down as far as I could over him, I felt his hands on my hips, and he started to move rhythmically inside me, lifting me again and again, allowing my body to sink over his, as he moaned my name.

Matching his rhythm now, I managed to regain something of my senses, and realised I still needed to tell him.

"Mark...", I stuttered, as he thrust. "Mark, I still have the condition." Another thrust. "And It is...", and another. "If you get to fuck Erin", one more. "Then I get..."

I could feel his muscles tensing now, and I was out of control myself. Lifting myself completely off his cock for a moment, I reached up and kissed him on the lips every quickly, and then thrust down again, impaling him, and pushing him over the edge. I was stunned to realise that I was coming again, and as I squeezed his pulsating cock, and we both panted with release, I told him.

"I get Matt!"

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