So despite the sad motive for our vacation to a tropical island, it turned out to be a birthday that I would never forget. Not only were we basking in the warm waters of the Caribbean, but I was also basking in the voluptuous flesh of my stepmother and my stepsister. After our morning romp that left me understandably drained, we all showered, ate a late breakfast, and completed a long walk along the white-sand beaches at our doorstep.

The trip to the Caribbean was a way to forget about my father's illness and death due to pancreatic cancer. The last several months had been an ordeal and we were thankful he went quickly. Our family had always been close, but his cancer cemented our love for one another.

Julie and I had discovered in our late teens that our parents were "swingers." Our numerous "uncles and aunts," as we called them, were actually close friends and, as it turned out, partners in sex orgies. When we finally asked about our discovery, mom and dad told us the whole story. It was an open and frank discussion. We were told that everyone involved was a consenting adult, and the group had strict rules as a safety net. The bottom line was that they all enjoyed sex and the freedom associated with that lifestyle, but getting to that point was a process. We were told that we would have to make our own decisions as the adults we were quickly becoming, but we should be careful about judging others too quickly. What they were doing was legal, if not exactly conventional.

"Don't rush into things," mom advised. "We are here for you if you have questions or concerns. No subject is off limits."

But as a result of dad's subsequent illness and death, my over-sexed stepmom had been necessarily celibate for some time. Our morning birthday tryst was the first real intercourse she had had in ages, not to mention the first intercourse I had experienced–ever. The desire to have sex with her stepson had come to a breaking point, especially after Julie described to her the size of my penis. My stepmother's obsession with large cocks got the best of her. She finally gave in to her desires despite the initial guilt of an incestuous coupling that plagued her. I also learned that Julie and mom had been intimate during dad's illness.

Julie was a natural caregiver, and one night as they comforted each other over tears, she ended up relieving her mother of built-up sexual frustration.

"We were just cuddling and smooching while watching a sad, late movie on TV. Mom was struggling with dad's illness, and I kissed her at one point. That prompted her to respond in kind. Her soft lips triggered something in me, and before I knew it, we were in each other's arms. Her huge breasts were pushing into me and I couldn't resist them. She opened her robe and suddenly I was suckling on her big nipples. We both got so excited that I ended up licking her in other places and using my fingers to get her off."

Julie paused to let that sink in. I was incredulous...and excited as I pictured my mother and sister in each other's arms.

"And we've repeated it a couple of times since then. It was weird at first, but then it also seemed natural. Mom is so wonderful and sexy! Mom went down on me and it was the most exciting sex I'd ever had. We decided that it was a loving thing but still needed to be kept between us. You are the only one who knows, Sammy."'

Prior to this disclosure, Julie and I had often talked about sex, and one late night in her bedroom we even discussed having sex with family. She felt it was fine as long as there was no coercion or pressure from either party.

"It's a natural act even though it is considered taboo. Of course, birth control would be necessary to avoid unwanted pregnancies if that is an issue, but consenting adults should be free to choose as long as it is legal."

Her talking that way got me thinking...and hard. She could see I was puzzled by what she said, and she reached over and hugged me tightly. When I felt those firm, teenage breasts poking into me, I kissed her cheek...and then I brazenly kissed her lips. That surprised her, so she returned the gesture with a kiss of her own. We ended up making out and lightly touching one another for several minutes on her bed. And then she looked at me with a big grin.

"Okay, we're NOT gonna have sex if that is what you are thinking, little bro, but I can see you are turned on. Do you wanna see your stepsister's boobs, Sammy? You are always staring at them. If you want, I'll end the mystery. They're just boobs, you horny toad. But no telling your friends. They'd think we are pervs."

Of course, I enthusiastically agreed, and Julie whipped off her top. Her white brassiere was stuffed with her firm flesh, and my heart skipped a beat as she reached behind, unclasped her bra, and slowly removed it. And there they were–the objects of countless jack-off sessions. Her breasts barely settled with their support removed. I was now staring at two perfect, gravity-defying cones; more than a mouthful and capped by large, pink areolas.

"Go ahead and touch them. They're firmer than Mom's but not as big. She says they'll grow bigger if I'm anything like her. Hers got huge when she was pregnant with me. Anyway, I'm pretty proud of them. I love to have them fondled."

I tentatively reached for a ripe nipple and before I knew it, I had my lips wrapped around one. With Julie's encouragement. I feasted on both breasts for several minutes as Julie cooed in delight. But too soon, she stopped me.

"Okay, Buddy. Now, it's your turn. Let me see your prick. Turnabout is fair play. Drop your drawers so I can see what you are hiding!" She had likely heard that I had a big one. Locker room talk has a way of spreading and I was no exception.

But, I briefly argued that showing my penis was not the same, but she insisted. So, red-faced, I did as she directed and when my undershorts dropped to my ankles, Julie gasped and put her hand to her mouth in shock.

"Holy shit, Sammy. That thing is scary huge! Wow, I never imagined you were THAT big. And thick. No wonder you are so horny all the time."

Of course, it didn't hurt that it swelled with the sight of her tits. It hung at an angle like a heavy polish sausage.

And before I knew it, she reached over and grabbed me. Her small hand immediately started to expertly stroke me causing my cock to stiffen even more. Her fingers could not encircle the shaft, and she marveled at the circumcised helmet-shaped knob on the end. She sat me on the edge of her bed, her eyes glued on her hand as her boobs jiggled with each stroke. I couldn't believe what was happening, and I reached out to fondle a bouncing tit.

It didn't take long before I grunted, and watched as a thick stream of sperm started shooting out of my cock and all over my sister's hand, arm, and even her breasts.

Julie let out a muffled scream and then giggled at the mess she had made.

"That didn't take long! Wow! What a load! Sorry, but I had to do that. I have never seen one that big. And you didn't seem to mind."

So, what started as a talk about sex ended up with my sis giving me a handjob. It was a one-time event up until this morning, but I relived it nearly every night after that in my dreams. When I wasn't picturing my topless sister's hand on my cock, I imagined me fucking my stepmom as her big boobs bounced under me. I was obsessed with my stepmom's breasts, especially after Julie told me about their late-night experimentation. I was jealous that my stepsister had been allowed to suck and play with those big boobs.

But as of that morning, that mental image was no longer a dream. And if things went the way I hoped, I would soon be plowing my admittedly large cock in and out of my stepsister.

When the three of us returned to our VRBO, we were already hungry again and decided to have lunch.

"Better replenish your energy; you're going to need it to satisfy two horny women." My mother winked at me lasciviously. "I intend to enjoy every aspect of this overdue vacation."

"On the other hand, don't overeat. I've got something for you to munch on, too." Julie blew me a kiss. Both she and my mother giggled.

Happily, I was no longer a virgin thanks to my mother's birthday surprise, and I had received my first blowjob simultaneously from both ladies as a bonus. Now, my sister was suggesting another bucket list item–performing cunnilingus. Of course, I knew the basics from watching porn, but I had no inkling of the nuances. Licking pussy sounded simple enough, but I had never actually done it.

Mom chimed in, "Your education is just starting, young man. We're going to make a stud out of you. You already have the tools. You just need some tutorials about how to use them. YouTube doesn't cover everything."

Julie looked over at me and laughed. "Better corral that horse, Sammy. Looks like he's ready to leave the barn."

My Speedos could not quite contain my excitement with their teasing small talk. The plum-sized head of my cock was peeking out of my waistband.

"Sorry! Guess I need bigger trunks."

"Well, you certainly don't need a bigger "trunk". The one you have practically crippled me this morning. I'm still walking stiffly. I'm out of shape, I guess." Mom opened the fridge. "Hey, birthday boy–want a beer? We're on vacation and you're old enough in my eyes...not to mention other parts of me."

"Sure. I'll drink a beer. Dad used to let me have one once in a while, and I like beer."

This seemed to be one more indicator that I had reached adult status. I tried to act casual as I expertly twisted the top off the bottle and took a swig.

After lunch, we sat around and did some reading in the sun. But soon, the heat and our libidos proved to be too much, and mom suggested we head inside and maybe take a nap. She used air quotes when she said the word "nap."

"Sounds great," Julie added. "How about your bed? It's big enough and if I recall, Sammy still owes me one." She pulled down her bikini top to reveal a large pink nipple. "Remember these?"

"How could I forget? Okay with you, Mom? Or would you rather be alone?"

"The more, the merrier. I've got the rest of my life to be alone."

So we gravitated to the master suite again. The bed was still unmade from our morning romp, and as soon as I saw it, my cock stiffened at the memory of my mother underneath me while my naked sister fondled both of us. I threw myself onto the bed and pretended to snore, my head buried in a pillow. In seconds the bed shook with the addition of two more bodies and I felt hands immediately grabbing my Speedos and pulling them down.

"Might as well get rid of these right now."

I rolled over onto my back and both Julie and mom had already removed their swimsuits and were laughing. My cock stood up like a Saturn 5 rocket and Julie slapped it playfully.

"Jesus, Sammy. Does that thing ever get soft?"

"Not when I'm around you two. I'm like a kid in a candy store. Only the sugar here is boobs and butts. Beautiful ones, I might add. Are we going to take a nap, or what?"

"Tell you what, Honey. It's Julie's turn. She mentioned you might need a snack, so I have an idea: let me show you the fine art of eating pussy. Julie, get on your back and let me give your brother a lesson in cunnilingus. If Sammy is like most men, the sight of two women snacking on one another is a huge turn-on. Besides, women automatically know how to please each other. But I'm betting Sammy's face will soon be covered in pussy frosting with a little encouragement."

Mom slid a pillow under Julie's hips and Julie leaned back against the headboard so she could watch the proceedings. My stepmother began by pointing out the dos and don'ts of oral sex. Julie's knees were pulled up to give us easy access.

"Start with just your tongue and slowly tease your partner, paying special attention to her little man in a boat, as your father used to call it. Julie inherited a nice big one, very much like mine. You may have to spread her labia gently, but don't overlook those lovely lips with your tongue, like this."

Julie's eyes fluttered as her mother gently caressed the area around her daughter's pussy with her tongue, adding kisses and pulling and sucking on those parts with her lips. Occasionally, she let her tongue drop to the little pink star of Julie's ass, eliciting moans of delight. After several minutes, she kissed me with my sister's juices on her full mouth.

"Now you try it."

And I did. I had always wondered about the taste, but to my surprise, there was nothing fishy about it at all. Julie's cunt tasted almost sweet. A little salty perhaps, but wonderful. With my mother's coaxing, I began to gently insert my tongue into my sister's opening, using it like a penis.

"Go ahead and lick all around it, too. Yes, just like that. Your sister has a beautiful, little tush. Mine used to be like that, but now I'm blessed with "more cushion for the pushing", as they say. Run your tongue around her little star and you'll drive her crazy, I promise."

As I worked over Julie, mom kissed and fondled her daughter's breasts and lips while she continued to offer compliments and encouragement to me. Julie's moans became louder and her hips began moving in response to my ministrations. She gripped my head with both hands and pressed me into that beautiful, fertile delta.

"Okay, you two, time for a change. I'm going to lie on my back. Julie, you get over me with your head by my thighs, and Sammy, you come back here so you can fuck your sweet sister from behind. I'll have a beautiful view of the action this way."

Jeanette positioned herself with her feet toward the headboard and Julie straddled her in the reverse. As I got behind my sister, her tight little ass glistened with my saliva. Mom added to it by licking Julie's pussy and then reaching up and placing my cock at the entrance to her daughter's vagina.

"God, I can't believe how big you are. I love it! Go slowly, Sammy. That thing is a weapon and your sister is tight. Start with just the tip." She concentrated on inserting me into Julie but teased the opening by running my glans up and down it first.

"There, the crown is in. Gently now. Your cock almost looks obscene from this angle. Hang on. Let me suck on it first so I can get it nice and slippery."

I dropped my cock into my mother's waiting mouth and she covered it in saliva before planting it back in her daughter. Julie was licking her mother's upside-down vagina but kept turning her head to try to see what was happening behind her.

"There! Finally, you're in. Now gently, Honey. It's tight, but pussies are resilient. God, this is so sexy watching you fat cock stretch your sister's tight little cunt. Mmmm, I can suck on your balls if you go slowly. Oh my god."

I felt her wet mouth engulf my balls one at a time.

I watched my cock slowly disappear in my sister, but fearing I would hurt her, I stopped it when I was halfway in. Her inner lips clung tightly to my shaft as I withdrew until just the tip remained. I pushed forward again and her pussy gradually opened to accommodate my girth. I built up my strokes until finally I was able to press my abdomen to her perfectly round ass. I had dreamed of this for ages, and now I was living my fantasy. I continued to fuck her using long strokes and burying my cock only to withdraw all but the crown. Periodically, I reached down and fondled her hanging nipples.

"Oh, fuck, Sammy. Jesus, you are so fucking big. Easy. It's a mix of pain and pleasure, but the pleasure is worth the pain. I only wish I could see it better. It feels like you're stuffing a baseball bat inside me."

"You should see it from my perspective, Honey. You're taking it bravely, I must say. God, you are already creaming over him. Pull out for a sec, Sammy, so I can have a taste."

I removed one hand from my sister's smooth ass and grabbed it by the base. I slowly withdrew my cock until it was free and clear of the moist cleft it had been invading and directed it to my stepmother's waiting mouth. I looked down and watched as she licked all around it, cleaning the milky shaft of our combined juices. When she placed me back inside her daughter's cunt, Julie gave out a little "oomph" and wiggled her ass backward to accept my fat sausage that was stretching her.

"I swear that thing would be reaching my tonsils if I had any. God, you are so deep. Just like that, Sammy. You feel so good. I am developing a new appreciation for my not-so-little brother. Just a little longer. I'm about ready to surrender."

As she spoke, I could feel a familiar urging...