Big Little Sister
Copyright© 2025 by OmegaPet-58
Chapter 4: In Through the Out Door
Young Adult Sex Story: Chapter 4: In Through the Out Door - Sisters Liz and Nat enjoy an above-ground backyard pool, inviting nerdy next-door neighbor Dan to join them. Nat is older, gorgeous, and the high school social queen, while Liz is heavy and feels overlooked. Dan, attracted to both sisters, thinks he has no chance with Nat, and soon he's partnered with Liz. Dan and Liz's deep intimacy is encouraged by Dan's single (and swinging) mother and the sisters' father. A simple teen romance explodes into lusty combinations.
Caution: This Young Adult Sex Story contains strong sexual content, including Ma/Fa mt/ft mt/Fa Fa/ft Mult Teenagers Consensual Romantic Lesbian BiSexual Heterosexual Fiction Humor School Sharing Incest Mother Son Sister Father Daughter Group Sex Anal Sex Exhibitionism First Flatulence Massage Sex Toys Voyeurism BBW Big Breasts Hairy Public Sex Size Nudism
Some days after our first time, I stepped around the dividing fence to join the sisters for a swim. I found Nat and Liz standing and batting a beach ball back and forth—topless, for sure, and probably bottomless as well. The water level was between their breasts and their navels, blurring the below-the-waist details—but I could see enough.
“Dave! Take off your stupid suit and join us.” Nat continued to tease me by calling me the wrong name.
“You’re not old enough to see me naked, Dorothy.” Tit for tat.
“Don’t listen to her, Dan; she forgets the name of the guy she’s screwing sometimes and has to grope around the floor to find his wallet and check his ID. But she’s right about your suit.”
I pulled out the waistband to check myself.
“Liz, that could be a problem just now.”
Liz put her hands up to make a flat shelf and rested her chin on them, with her head tilted. Blinking prettily and smiling, she wheedled, “Please? Pretty please?”
I folded like warm laundry and bent down, intending to tug them down low enough so I could step out.
“Stop!” Nat ordered. “Turn around.” She wanted to see my ass?
I straightened up, shrugged my shoulders, and turned around. Nat made a drum and cymbal “boom-chicka” soundtrack as I wiggled my ass at the girls while pulling the old suit down to my ankles. When I turned back to face them, my hard-on was still developing but seemed to be about three-quarters towards full.
“Oh, wow. Liz, you and I need to set up a routine, like I have him on Mondays and Thursdays, and you have him the other days. A sharing sisters system—what do you think?”
“I think if I catch you with Dan, I’m going to shave your head bald and put ghost pepper sauce on his dick.”
I wasn’t even aware of my hands rushing to cup my crotch protectively. I reacted badly to even the mildest salsa; how did Liz know this?
“Daniel! Move your hands!” When Liz used her voice this way, I had to obey. Swiftly.
“Yes, mistress.”
“Before you answer my questions, I’m telling you there’s a bottle of ghost pepper sauce in our kitchen. I expect truthful answers. Do you understand?”
“Yes, mistress.” I was tempted to tell Liz, “Yes, Drill Sergeant!”
“Good answer. Question one: is my sister hot and beautiful?”
I had to go with the truth. “Yes, mistress.”
“Question two: if Nat’s in your bed with her legs spread wide and her pussy was wet and glistening, would your dick be hard?”
Hell, it was hardening further, just by imagining Nat in that pose.
“Yes, mistress.”
“Question three: would you accept her invitation and plunge your hard cock into her hairless pussy?”
“No, mistress. Not in a million years!”
A pout marred Nat’s cute face, while Liz exulted. “YES! Now get your ass in this pool.”
I climbed the little stairs. For a moment, I was tempted to sit on the top step and dangle my legs widely for Liz to come and give me a blowjob. I didn’t want it with Nat right there, though.
We started tossing the beach ball back and forth. Then, I realized the girls were “accidentally” letting the ball bounce out of the pool so I would have to climb out and get it. The two of them were ogling my butt and bits as I used the stairs to climb out and back in—the same way I had been watching their asses when they exited the pool.
All of the in and out (of the pool, mind you) began to irk me, and Liz picked up on my frustration. She announced it was time to get out so I could massage her. The loungers were now positioned in the shade, so instead of sunscreen, we’d upgraded to a much more palatable massage oil instead.
This was the first time Nat had seen me massage her sister, and she was fascinated—perhaps even jealous. In spite of my rampant hard-on, I kept the massage as non-sexual as I could. Nevertheless, Liz’s groans and moans couldn’t be misinterpreted. I watched her pussy’s natural lube dripping onto the lounger’s fabric while the familiar scent of aroused Liz curled into my nostrils.
“Liz, I was going to ask, ‘Where did you find this guy?’ But I know the answer. Dan, what can I do to influence you?”
“Influence me, Nat? You want a massage?”
“I want every single thing I can get from you that Liz will allow. I’ll wash your clothes; I’ll wash your dishes; I’ll mow your grass. Just name it.”
“Nat, that’s tempting. But I could never do anything with you without permission from Liz. I can’t promise my dick will stay soft with my hands on your body. How about this: have your boyfriend come over to swim with us, with everybody wearing swimsuits. I’ll give him some coaching on massage techniques, so he can be your ‘Massaging Dave.’ How about that?”
Nat sounded very disappointed and looked away. “I guess.” She stood up and disappeared into the house without another word.
“What did I say?” I asked Liz, confused by her abrupt exit.
“Let me explain Nat to you this way. Nat has had plenty of boys, but never a boyfriend. She doesn’t trust them; sometimes, she doesn’t even LIKE them. They come, uh, yeah, they come, and then they go, and it’s on to the next. She can’t imagine letting any of them get close enough to be a massage partner.”
“I’m beginning to understand why you aren’t so jealous of Nat lately. She’s queen of the school but not enjoying herself.”
“That’s right, Dan. She wants a royal consort who is warm and loyal, but instead all she sees are lecherous peons, or something.”
“Some day, my prince will come?”
“Exactly. For the first time, Nat is jealous of ME. Because of YOU, Dan. Watching you massage me aggravated her feelings.”
“I don’t know what...”
“Relax, Dan. This is a problem for me and for Dad to work on. For now, even if Nat flirts with you, you have to turn her down. You know, like a good massage: gentle, but firm.”
“Yes, mistress.”
“Jeez! You keep saying that. How am I going to resist you?”
“You won’t, I hope.”
“Yeah, I’m a slut for your obedience. But I will send you home now. Nat is going to take out her frustrations on me and Dad.”
“That sounds terrible. Are you sure?”
“Yeah. Have a quiet evening with Irene instead.”
“OK, that’s a good idea.”
I walked into our kitchen through the back door. Mom was starting on dinner, wearing her new normal, just her small apron and nothing else.
“Howdy, stranger. I’m Irene. Are you here for some chow, or are you just sightseeing?”
She thrust out her chest, preening for my benefit.
“Can’t I do both?”
“I guess so. You seem familiar, somehow. Are you Dave or David?”
Oh, no! I wondered how she had that name. Liz? I decided to continue the game.
“It’s a shame how your son left you alone without any male companionship. Should I dress for dinner?”
“Why, yes, that would be best. Is it just you and me tonight?”
“Yes, Mom.”
“Mom? There’s no ‘Mom’ here, Dave, just Irene. You think I dress for dinner this way normally? Don’t answer that! Get rid of your clothes, then come back and have a seat.”
When I returned, Mom had plated our dinners and put down little towels for us to sit on.
“So, Dave, we’re on our own tonight. Is your other girlfriend Beth unavailable?”
“That’s right, Beth is having dinner with her father, Bradley, and her sister, Gnashtisha.”
“I see...” Mom burst out laughing. “Gnashtisha?”
“Yeah, spelled with a ‘G’—like ignorant.”
“Oh, fuck.” Still laughing, “Alright, Dan, I surrender. I just wanted to imagine a little romantic dinner with you.”
“Mom, you’re still my number one girl. And I’ve never lost my enthusiasm for your big, beautiful breasts.”
“Don’t tell me this in front of Liz. She still worries that she isn’t attractive enough, and you’ll dump her in favor of Gnashtisha, sorry, Natalie, or some other foxy young lady.”
“Not going to happen, Mom.”
“You should be prepared, though. Romances at your age usually have an end point. Some guy with lots of money and a big cock ... I guess that wouldn’t be a selling point, or pointer. You’re plenty big enough, based on what Liz says and what my eyes tell me.”
“That reminds me,” I responded. “Something you said, a long guy like me wouldn’t hit bottom if I went into her butt instead. Oh, no—that’s some kind of terrible pun, sorry. But how would that work?”
“Tell you what, Dan. Let’s finish our supper before we discuss that topic, yes?”
“You’re right, Mom. How was work?”
As usual, that question triggered the usual list of complaints and irritations. Mom was in the uncomfortable situation where she made too much money to quit or change jobs without taking a big pay cut. Her bosses kept throwing money at her because it would take three new hires to replace her, Mom said. Instead, she depended on my evening massages to recover from her long days pounding the keyboard. Mom even purchased a folding massage table with a hole for her face.
Lately, she became more open; her ass was no longer off-limits. I couldn’t help but compare it to Liz’s bottom; Mom’s was softer and bigger, yet still shapely without any dents or signs of age. I was reminded that we were only fifteen years apart. As I massaged her, I repeated my question.
“Son, do you know the word, ‘enema’?”
“Sure, it’s like Spanish, one of those gendered nouns. He is my enemy, but she is my enema.”
I heard a loud snort. “I love you to pieces, Dan, but you’re an idiot. An enema is when you fill someone’s rectum with a warm solution using a syringe. Then, they sit on the toilet and expel everything, so their back passage is clean and empty inside. Got it?”
“I guess. Is this sexy and fun?”
“I believe some people think so. But I’m telling you about enemas because they are a good preparation for anal sex, along with lots of lube. You don’t want to be crowded while you’re inside there.”
“I suppose not. What confuses me is why a woman would bother with an enema?”
“Because, fruit of my loins, you can’t get pregnant leaving sperm at the Department of Shitting. And many—I think most—women enjoy the hell out of anal sex. The wiring between front and back in the pelvis is all interwoven. If you watch carefully, her asshole twitches in regular pulses when she comes.”
“Oh, I guess I’ve noticed that. Maybe tomorrow night I can have Liz come over and we’ll try it.”
“That would be a good time. I’ll be overnight at the Mitchell’s.”
“I have to babysit Lisa?”
“No, their daughter is staying with her aunt and cousins at their house. You’ll find an enema kit under the sink, and you can borrow my lube. Remember that the back hole isn’t naturally slippery; you need to remember to use lube.”
“You’re the best Mom, you know. I feel lucky.”
“You ARE lucky. If I didn’t have the Mitchells to play with, I’d be seriously contemplating an illegal act with you.”
“And, if I didn’t have Liz, I’d be on top of you for more than a massage. Hey, do you mind if I use your table to massage Liz?”
“No, provided you clean it up afterwards.”
“Of course, Mom.”
At school the following day, I found Liz at lunch. She was in a foul mood and showed signs of having recently cried.
“Oh, no! What happened?” I asked.
“Nat was in a terrible snit last night. She fought with both of us, saying nasty things and blaming Dad for all her problems. She shoved my father when he tried to hug her. I’ve never seen her like this.”
“Did she hurt you?”
“No, let’s just say I’m well padded. But she screamed at me and blamed me—and you—for her being miserable.”
“What did *I* do?”
“You’ve been perfect and supportive and sweet. When you make love with me, it’s more than just sex. This annoys her. Apparently, her latest guy refused to go down on her in return for a blowjob, and when she complained, he told her to get lost, along with a bunch of filthy lies about her pussy smelling bad.”
This confused me. “Liz, this doesn’t make sense.”
“No, it doesn’t. I try not to talk about you, for this very reason. But she probes and probes, asking for details, even though they’re none of her business and they just make her angrier. It’s like she’s picking at a scab that doesn’t heal.”
“I wish there was something I could do. Should I be mean to you, Liz?”
She cracked a smile. “No, that wouldn’t help. I swear, she’s been bent out of shape since that last big blow-up with our mother. It would all be different if Irene were her mother or stepmother. Say, maybe I should bring my dad over to your house again. What do you think?”
“Well, not tonight; she’s going to be off overnight with her friends, the Mitchells.”
“You’re babysitting?”
“Nope, I was going to invite you over tonight. My mom had some suggestions for us tonight, which I can’t talk about here at school. That was before I saw how upset you are today.”
“No, being with you sounds perfect. I need a break from Nat’s drama, and I think it’s better if she and Dad deal directly instead of involving me. I’m not giving you up, Dan, so let’s have a nice evening together.”
The remaining hours of the school day crawled along until finally the last bell at 3 p.m. released us from bondage. Sometimes, Nat walked home with us, but not today; we saw her depart with another guy, a senior. While we walked, Liz pressed me for details about tonight.
“Dan, my love, the word for today is ‘euphemism.’ You talk around things, particularly sexual things. You don’t say anal sex; instead you say, ‘door number two.’ Can you just tell me clearly what’s going to happen tonight?’
“Mom said we could use her massage table, as long as we clean it up afterwards.”
“That’s nice, but you have more to say, don’t you?” Liz was not satisfied with my answer.
I admitted, “Um, like you said, door number two.”
“Oh, Dan, you’re all pink. Where does this shyness come from? Your mother flings her clothes off now the minute she gets home.”
“She does NOW, Liz. When I was younger, she never—I mean, never—swore. She’d say things like ‘horse apples’ and ‘bull feathers.’ When I got into high school, my vocabulary expanded, and I accidentally swore in front of her. But the consequences I imagined didn’t happen. I think she finally put away the last shreds of her miserable pre-pregnancy life and loosened up. But sometimes I still police my language. I’m sorry, it’s just a quirk.”
“Nah. It’s part of your charm, Dan. You think I should go around complaining? ‘Oh, poor me, my boyfriend uses euphemisms!’ Nope. You can call sex anything you want, as long as you actually do it.”
“You’re the best, Liz.”