"Oh, fuck, that's tight!" I declared as I drove deeper inside Nina's arse, enjoying her gesture of complete surrender to me at a time when my own wife wanted to effectively enslave me.
Nina tried to speak for a second before she recalled that her mouth was busy licking Heather's bum, something that our guest seemed to relish in no small measure. We had gone at it for some time now, forgetting about the pool and anything else as we fucked much of the day away. It was just too great, the way that our three bodies meshed and melded, fused seamlessly into one flesh, our skin on each other's skin. My cock was very sore and so was my mouth, but it was more than worthwhile to pleasure my sweet ladies. It was glorious, the best that any of us ever had, bar none.
"Oh, Dios mio! Keep that tongue working back there, mami! I'm yours ...and his! I belong to both of you now! Just...keep me...please!" Heather begged us both, making it clear that she was our bitch.
"Alright, baby! Here it comes!" I declared as I shoved my cock balls deep inside Nina's delectable culo.
Staring down at my fiancee's wondrous cheeks and admiring them, I lost it completely and exploded in her pucker. Her arsehole now leaked my jizz and she winked back at me before she returned to her task of licking Heather's bottom. When I leaned down and started cleaning up my own mess as it oozed from her arse, Nina moaned louder than she ever had in her life. The excitement of our menage a trois really caught up with her by now, just as it had for me. There was a delicious new pecking order, one with me at the top, followed by Nina, and only then Heather. I made a note to check and see how much I could keep her nude, because doing so would be a very nice bonus for me. If I could keep Nina naked, too, even better.
"What are your thoughts on waiting until later and darker, and then swimming in the nude?" Nina asked me, much to my surprise.
"Which of us?" I asked, just to be clear.
"Just me, unless Heather wants to join me in skinny dipping. What do you say, Heather?" Nina asked our companion as she drove her to a climax at last.
"If Master and Mistress command it, I'll gladly do it. From now on, I want to live with you full-time. I'm not sure what this will do to my marriage, but I no longer care. I've realized that even an open marriage pales next to a lifetime of service to my owners. I really want to be your plaything, your sex slave, your fucktoy, plain and simple. To both of you. I want to be owned by a couple. It's always been a fantasy of mine, to be the perfect unicorn, the absolutely submissive cum-slut for man and wife alike. I'm not a switch. I'm a natural-born sex slave, period. Please make me your bitch!" Heather encouraged both of us now.