“You can’t be serious! This is less than a month from April’s Fools Day. It must be a joke!” I told my sister, who indeed seemed to have a hard time keeping a straight face.

“Nope, I’m in earnest. It’s a serious idea! I want this! I’m your sex slave, bro! I need this, you need this, and it’s going to happen. Just collar me, honey. Please! Lenny understands, don’t you, babe?” Karissa turned to her boyfriend, Leonard “Lenny” Miller, Jr.

“Absolutely, dear. Look, this is what my girlfriend needs. It’s fun for all of us. She’s still my girlfriend, but she’s your slave by her own volition, and so you might as well enjoy her,” Lenny told me, making my cock stiffen, even as I blushed a bit, especially in the presence of my girlfriend, Eva Nunez, who hadn’t spoken a word, just watched and listened while nursing her martini.

“And your thoughts, babydoll?” I asked Eva at last, using my favorite pet name for her.

Unexpectedly, Eva brightened up and told me, “Just do it, papi. Don’t think about it, don’t worry about it, don’t stress it or sweat it. Adam, honey, it’s quite simple. I love you. I love so you much that I want you with all the territory that comes with you, and that includes a long-standing sexual chemistry between you and your baby sister. I don’t want you to have any regrets in your life, things that you could have done, but didn’t due to me. This isn’t about my needs or Lenny’s needs. This is about your needs and Karissa’s needs.

“And, yes, it’s totally necessary that she be the submissive, because that’s what she is. She’s submissive. And she needs a Dom who will love her and take good care of her, one that she can love and trust. Well, she loves and trusts Lenny, but he’s no Dom and he’ll tell you that himself. To be honest, both Lenny and I find it a serious turn-on, the whole thing. We’ve discussed it more than once. We like bondage, whips, chains, etc. in the abstract, but we’re not really comfortable with facing the reality in terms of it affecting us directly. It’s kinky and hot, but it’s not something that we could actually do in real life ourselves.

“Add to that the incest, and God, that’s just steamy as hell! If this works, we could all live together as a household of sorts, if that’s okay with you, and we could have such fun, perhaps even benefit indirectly in some ways from your D/s relationship with Karissa. Come on, baby, just do it. Just claim and collar your sister. Make her your slut. This will not be deemed cheating by any of us, since it’s done with our freely and gladly given blessing.

“More important than anything else is that she needs this and I think that you do, too. I love you too much to ask you live without the love of a good woman, in this case your sister. You’re not a possession, but she is, or rather she wishes to be. Your possession. You want this, Karissa wants this, Lenny wants this, and I want this. So, how about it, papi? You in or out?”

It wasn’t just Eva’s bright, eager smile and question, nor Lenny’s obvious voyeuristic anticipation, but Karissa’s sweet, baby blue eyes, that finished off my doubts and scruples about claiming my sweet sister as my pain slut and sex slave, of course. Yes, I suppose that I should mention that part. Karissa didn’t just want to submit ... she wanted to be used, punished, hurt, and taken for my pleasure. Her eyes made it plain that she really craved and needed this, this thing that her boyfriend Lenny never could give her or do justice himself with it. She needed to become my property, my slave, my slut, my bottom ... my bitch!

“Very well, then, sis, but be careful what you wish for, because once you get it, there’s no turning back. Are you ready to sign away your freedom, sis? This is no joke. This is serious business and you know it. Are you ready for the consequences, slave? If you do this, it starts now and it never stops, so think long and hard about this. If you mean what you said, crawl to me and bring me your collar with your teeth. I will collar you, but once I do, I expect you to tear off your clothes and spend the rest of your life in the nude, wearing only what I please,” I warned Karissa, who gulped, licked her lips, and did exactly what I asked of her, including the teeth bit.

“Master, please ... please collar me!” Karissa begged me, her eyes very wide and eager as she knelt in front of me.

“Well, I am a man of my word, am I not? Very well, then. Prepare to be collared,” I told my sister.

So it was that I, in the full sight and presence of my girlfriend and her boyfriend, placed a collar around her neck, marking her as my slut. From now on, Karissa belonged to me, even though she would still date Lenny and I would stay with Eva. In fact, I wanted to keep Eva even more now. I had an idea, but I wasn’t sure how Eva would take it.

“Eva, have you thought of how this might affect our future relationship, if we have one? Most girlfriends tend not to want their boyfriends keeping their sisters as sex slaves, though thankfully, you’re clearly NOT most girlfriends. You’re an above average girlfriend as it is, let alone adding your sensible approach to sharing and your control of your jealousy. I would certainly like to keep you as a girlfriend, and I love the idea of us sharing a house.

“Even so, it’s not fair to Lenny that he probably wants to get married and now that’s out the window. I mean, it’s one thing for a girlfriend to be her brother’s sex slave, and it’s another thing for a wife to have a lover, but it’s illegal under the new Domestic Bondage Act here in Missouri for a slave to marry, isn’t it? This means that Lenny can’t marry Karissa, not now that she is a slave and will have to be registered with the Office of Voluntary Service. What a hoot, that, using euphemisms to pretend that this isn’t chattel slavery because people initially volunteer for it! Clever loophole to use in the Thirteenth Amendment.

“This was quite a sacrifice that Lenny made, just to make Karissa happy, don’t you think? So, here’s my idea. A slave can be a girlfriend, as that relationship isn’t legally binding or official in any way. Karissa will remain his girlfriend, just as she is now my slave as well as my sister. So, you will remain my girlfriend, but you should become his wife. Marry Lenny, be a substitute for Karissa, but still date and sleep with me. It’s not that I don’t love you. It’s that he wants to marry and so do you, and this is the only option left that allows both of you to wed.

“This is a sacrifice for me, too, not getting to call you my bride. Trust me, though, it’s for the best. It also allows our quad to be complete, because, presumably, as Lenny’s wife, you would have sexual relations with him, just as you will continue to do with me as my girlfriend, and Karissa will continue to do with Lenny as his girlfriend. Of course, this requires your consent as well as his, but it makes all the sense in the world, especially if we’re all living together and would eventually end up all having sex with at least the opposite sex members in the same house.

“You would have ended up sleeping with Lenny, anyway, I think, but this neutralizes the potential hot buttons for conflict about that, such as feelings on my part or Karissa’s that there was some kind of cheating, plus it removes any sense on Lenny’s part at the outset that he is a cuckold because he’s the only one without a second partner. He has clearly dealt with such potential issues to an extent, but they probably still lie dormant in his subconscious. Marrying my girlfriend should do much to resolve that,” I proposed to my girlfriend and Karissa’s boyfriend my rather radical idea.

“Mmmmm ... marrying Eva? Wow! That would be terrific, since I can’t marry Karissa, that is. I also like the idea that if Eva gets pregnant, there is a legal father, if you don’t mind my claiming whatever children are born to her. It’s only right, since presumably you’d be listed as the father of Karissa’s children, being her Master. We won’t know for sure, of course, unless we choose to test the DNA, but I think that we should simply presume paternity unless or until there are medical reasons to examine things closer. I also like the sense, just as I in one way gave you my girlfriend, you’re giving me yours. If she agrees with it, of course,” Lenny smiled, even as Eva leaned over to kiss me on the mouth.

“Papi, that is the sweetest thing you could have ever done, short of what you already did! You took pity on poor Lenny and gave him a wife! Thank you for being such a nice man! I promise, I will do as you ask and marry him, but I will remain your girlfriend as always, and yes, I will sleep with both of you, just as Karissa will. She might be a slave now, but she’ll still get to share the two greatest guys in the world with me! We’ll share a house together, then, as I suggested? Maybe the four of us in one bedroom and one bed? Delicioso! I can’t wait to make some real Cuban food regularly for the four of us!” Eva said sweetly, even as she patted Karissa on the head.

“That’s what I was thinking, yes. We all have our relationships. Karissa is my slave as well as my sister. Both of those are for life. She is also Lenny’s girlfriend, for life as well, unless he dumps her, which I don’t think that he’d ever do,” I observed while kissing Eva and stroking my sister’s hair.

“Never. I’d never dump my Karissa!” Lenny assured us, “Nor would I ever divorce Eva! She’ll make such a wonderful wife, I can already tell!”

“Plus, I’m Catholic, sweetie. We don’t divorce! It’s against the Church and the sacrament of holy matrimony!” Eva reminded him.

“Which brings me to the next relationship set. Eva is now Lenny’s fiancee and will soon be his wife, but she will remain my girlfriend. So that’s four relationships right there. Eva’s with me. Eva’s with Lenny. Karissa’s with Lenny. Karissa’s with me. They’re distinct and in some ways unique relationships, but each will co-exist happily in one home, I think,” I noted, enjoying the softness of Karissa’s amber locks in my hands and Eva’s kisses on my neck.

“Know what other relationship we should have? To really complete the quad better, if you don’t mind, and granted that this was an ulterior motive for a while now ... I want to borrow Karissa now and then, so that I can make love to her. I know that might be a shock to her and to you, but I think that I’m bisexual and I want to try a woman that I can trust. Who better than my boyfriend’s sister and sex slave, who also happens to be my fiance’s girlfriend? What do you think?” Eva added her two cents.

“So, wait, you won’t divorce because you’re Catholic, but you’ll sleep with Karissa and do lesbian stuff with her? Fascinating!” I laughed.

“I’m Catholic. We’re a horny, sinful bunch, but we also have a deep faith and follow the will of God in our own perverted way. Think that’s an inconsistency? Just remember, have I ever once gone on the pill? No, and I won’t. I’ll slut it up with the three of you, commit adultery and Sapphic sin, but I must have a Catholic wedding and I insist upon no condoms or other forms of birth control! No abortions, either! And I will insist upon my boyfriend’s sister as godmother for my babies, all of them!” Eva laughed, but I could tell that she was in earnest.

“Well, as understanding as you have been, and as kind, even to the point of marrying Lenny to replace the potential wife that he lost in Karissa, I’m certainly not going to object to you muff diving, babe. I almost envy the priest getting to hear about it in the confessional, though only almost. After all, I’ll get to see it for myself, not just hear about it in a sweaty booth and have to go home and masturbate,” I chuckled as I watched Lenny put kisses up and down Karissa’s spine.

“This really turns her on, just so that you know,” Lenny told me with a grin.

“I can see that,” I noted the shivers and goosebumps that followed Lenny’s kisses along my sister’s back, “Eva enjoys being bitten on the bottom. Not roughly, not enough to break the skin. Just playful bites on the buns themselves.”

“It’s true! I do! I love it! It’s so ... aggressive, but in a loving way. Very intimate, too. I wouldn’t trust just anyone to bite me on the ass, I can tell you that!” Eva confessed, offering me her booty for just that purpose ... and sure enough, I started biting it, which made her squirm.

“Slave, make love to my girlfriend Eva, right in front of us,” I instructed Karissa now, testing her obedience, “Not rough sex, either. Gentle lovemaking, between two ladies. Kiss, lick, caress each other.”

Karissa didn’t hesitate, reaching for Eva, who willingly joined her on the carpet. The next thing that we knew, the two ladies had their bodies pressed to each other, Karissa’s pale flesh caressing Eva’s swarthy skin. Pretty soon, Eva’s thighs were parted and Karissa’s tongue slid between the folds of her pussy, licking and tasting, even kissing her down there. Eva bit her lower lip as she experienced Sapphic pleasure at last, her lesbian virginity lost for good. I could tell that she was hooked on the delights of her own sex for sure and that she wouldn’t give it up for the world. I could sense that Eva had fully embraced her attraction to the fair sex at last and that at least one new relationship existed between the four of us.

“So, Adam, the girls are ... enjoying each other. Would it be okay, and bear in mind that I know that you’ve never done this before, but would it be okay if I sucked your cock now?” Lenny asked me, albeit timidly, “I would like this quad to be totally complete. What do you say? You don’t have to do anything like take a dick up your butt if you don’t wish it. I just want to show my gratitude, both for agreeing to enslave Karissa and for sharing Eva with me. How about it? May I suck your dick?”

Maybe I had too much JD in me right then, and maybe I was already too horny thanks to all of the dirty talk and the sight of two women rolling around on the carpet, one servicing the other quite selflessly, but I was in no mood to decline a blowjob, not even from another man. After all, I reasoned, if I were intimate with Lenny, it would further seal the bond between us as a quad, would further add to the sense of a family and such. I nodded and spread my thighs wider, as Lenny knelt and began his tentative first kiss to my cock, starting with the head of it.

I shivered from the first sensation of Lenny’s lips and tongue along the head and opening of my dick, after which he started to run his tongue along the length of it to the base. I started to move my hips in appreciation of his oral services, and it wasn’t long before he had engulfed my entire prick in his mouth. He really got into it now, and I soon realized that he was deep-throating me, my cock gagging him with its length and girth. There was no question now that Lenny was bi and at least a bottom with me, if not with other men. Perhaps he didn’t trust other men enough to submit to them that way, though his submission was very vanilla in nature ... He really didn’t want to do anything too kinky. It just wasn’t him. He just wanted to bottom.

I fought back the urge to cum just yet, but it was far too much stimulation, especially once Lenny began playing with my balls and his fingers found their way to my asshole. The level of arousal intensified and I tried to warn him, but he kept up servicing me as if his life depended on it. I continued fucking his face, but at last I couldn’t hold back with the wonderful warmth of his mouth and I shot my load down his throat, a massive moneyshot that had him really working to swallow it. I pulled up him to me on instinct and aggressively claimed that snowball kiss from my buddy, whose knees nearly buckled, especially once I grabbed his junk and began angrily pumping him.

“Oh ... fuck!” Lenny shouted, especially as we noticed that Eva and Karissa had switched places, my girlfriend now munching on my sister’s twat with a vengeance, which made Karissa’s toes curl.

“My turn, bro!” I said, giving him the handjob from Heaven, at least from what I could tell.

I played with his balls as well as his cock as he shuddered and shot out enough jizz to knock both girls up. Then I put my shrunken dick to Karissa’s lips and gasped as she opened her mouth to accept me that way. She knew that her boyfriend had just licked and sucked that very same cock and she seemed to really perk up at the prospect of following him that way. At the same time, Lenny went behind Eva and licked everything from her toes to her booty, back and forth, switching between both legs as well. My girlfriend definitely reacted with excitement to that kind of attention.

Just as Karissa came at last from Eva’s oral favors, I pulled that sweet blonde sister of mine up and bent her over the armchair. My dick was semi-hard at this point, so I simply rubbed it between the cheeks of her pale bottom to help arouse me again enough to take her. It was time, wasn’t it? It was time to claim what was mine at last. It was time to fuck my little sister into next week. She knew it, too, as she pushed back at me with her fine, fair hips. She knew what I wanted, as it was what she wanted, too. She knew that I desired to fuck her, to claim my rights to her body at last.

In fairly short order, I was balls deep inside my sister, taking her sweet, slutty snatch for my own pleasure as well as hers, my cock pulsing as it thrust in and out of her depths. I screwed Karissa for the sheer hell of it, my hips moving furiously as hers cooperated with them, showing just how eager she was to be my sex slave after all. My baby sister looked like a fucking cheerleader, which she had been in both college (which she had only graduated the year before) and high school, and here she wanted badly to be pounded in the cunt by her big brother, the nerdy history teacher, of all people! I humped her good and hard right then, my cock not showing her any mercy at all. At twenty-seven years of age, I was finally fucking my sweet sister, the one that I had secretly desired since her adolescence.

Meanwhile, of course, my lovely girlfriend Eva was engaged in riding her future husband Lenny cowgirl-style, her breasts more than delighting him as she waved them directly in his face from above. From the way that she rocked him, he had to be getting carpet burns on his ass and the back of his legs, but he didn’t seem to mind. After all, he was finally inside Eva, for whom he had apparently lusted for a considerable length of time now. Who wouldn’t want her, in fact? At twenty-three years of age, my Cuban sweetheart knew exactly what to do with a man’s body and how to make him crave her for life. She was every bit as sexy in her own hot, sultry, Latin way as my fair-skinned sister, Karissa, was, of course.

It was also clear to me that I had made the right choice as to marriage arrangements. Eva could handle an independent boyfriend, even one with a slave, but for a husband, such things could lead to conflict. Her hubby needed to be the “yes, dear,” type, for everyone’s sake, including his own. Only a henpecked man would do, and Lenny would certainly fit that bill. Once that ring slipped onto her finger, if not before, Lenny would be kissing her ass (granted, it was a very sweet ass) and doing exactly what he was told.

Eva and I would have been fighting inside of a month of our wedding, if not before. Lenny, however, would simply roll over and heel like a good little bitch. His submission might be of the more mainstream variety in how it manifested itself, but he was at heart the compliant sort of man, both in terms of bottoming for me and in the sense of obeying his lady. Luckily for all of us, Eva’s idea of dominance was expressed in very sensual and seductive ways, and despite her aggressive nature, she honestly wanted everyone to be happy. I had the feeling that had I married her, and there had been no Karissa or Lenny, she would have wanted to put me out to stud and join lovers of both sexes with me in the marriage bed.

“Oh, fuck meeee, Master!” Karissa begged for more, as I continued my furious strokes inside her glorious twat (and yes, the curtain matched the drapes, though I had her shave it afterward).

“You want this cum inside you, don’t you, slave?” I taunted my sister-slave as I humped her, still bent over the armchair.

“God, yes! I’m yours! I meant it! I’m your slut! Give me your cum, please!” Karissa exclaimed, pleading for my spunk and more of my dick, of course.

“Me, too, Lenny! Shoot me up with your seed! Knock me up!” Eva urged Lenny, who had a very hard time saying no to her as it was ... there was no way that he wouldn’t cum after hearing that demand!

Sure enough, Lenny came inside Eva’s wonderful twat, filling her with his jizz, just as I struggled to hold back amid listening to Eva and Karissa both cumming now. I gave up the fight, my balls pushing the cum through my dick into Karissa’s pussy, completing the act of incestuous passion at last, just as I heard a cough from the hallway. It was Mom and she looked very shocked indeed, to see clear signs of what could only be described as a full swap, and an incestuous one at that. We must have been fairly loud to be heard over the sound of her TV that she always played in order to help her sleep.

“Mom, you might want to sit down for this,” I told her at last, though I was stunned to see a smile creep across her forty-five year old lips.

“I wondered what you guys would do the moment that you didn’t think that you were being watched, and quite frankly, I wasn’t disappointed. Stunned at the ease and comfort with which you would finally hook up with your sister, Adam, but not surprised over all. All that I had to do was pretend to be asleep. What I’m about to tell you next, well, you guys might want to sit down for it, too,” Mom invited us into the kitchen, all of us naked as jaybirds still.

“Another martini, Eva? Jack Daniels and Dr. Pepper for you, right, my son? And while it’s clear that Karissa is now your slave, perhaps you’d let her pick a drink, since she is your only sister in the world and I know how much you dote on her. And, you, Lenny, what do you want? More tequila? I’m going for a rum and Coke myself. They help me relax and possibly sleep, though I’m not sure how much I’ll sleep tonight. It’s not everyday that I find out that my daughter is now her brother’s chattel. Clearly, the four of you are okay with this, so let’s see what we can work, shall we?” Mom continued while mixing drinks.