Well, we've got incest of various varieties, impregnation from said incest, loss of virginity, size kink, and an orgy with the resulting exhibitionism/voyeurism.
For reference:
Lizzy, 18
Kate - Lizzy's mom, 38
Joe - Lizzy's dad, 38
Martin - Lizzy's uncle, Kate's brother, 39
Nancy - Lizzy's aunt, Martin's wife, 41
Rob - Lizzy's grandpa, Kate's dad, 59
Hope you enjoy!
-- -- -- -- -- -- -- -- -- --
"Lizzy, honey-- You've really got to get out of bed! Your aunt and uncle will be here soon."
Kate rolled her eyes as Joe -- her husband-- yelled to their daughter. "She's such a teenager," she chuckled.
"Oh, absolutely. But come on, don't tease her today: it's a big day for her."
Footsteps sounded, and Lizzy soon entered the kitchen.
"Geez, stop yelling. I'm awake! I was just getting ready."
It was clear Lizzy was telling the truth: her blonde hair was damp from a recent shower, tugged over one shoulder. It was long, hanging down below her breast, and usually tied back in a ponytail that swung when she walked.
Lizzy was small in nearly every way -- short, nearly flat-chested -- except one: she had muscular legs and a round, firm ass courtesy of years as a cheerleader.
"Good," Kate said. "We've got to get ready."
Joe and Kate had been together since high school; they had Lizzy soon after they graduated.
Kate was just below average height, though still taller than her daughter. Her hair was the same shade of shiny blonde, but it was cropped to her chin. She was just on the edge of overweight, but the curves sat well on her, giving her wide hips and that same round rear.
Joe patted this very ass as he brushed by his wife, earning himself another eye roll. He was a lean man, bordering on scrawny, with ginger curls that he kept gelled into neatness.
"Are you ready for today, Lizzy?" he asked.
The teen bobbed her head in a nod. "Yes, daddy. I'm ready. I'm so happy I'm old enough to join seeding day this year!"
"You're lucky your birthday is when it is," her mom agreed. No family member was allowed to participate in seeding day until they were an adult, of course; in fact, any children of the host were sent away for the weekend. Lizzy had turned eighteen a mere week before.
"When will everyone be here?" Lizzy said, impatient. "I want to get started!"
This got her laughs from both parents. "Soon, honey," Kate said. "I'm sure they're close. But Lizzy--" Her mother paused.
"What is it, mom?"
"I just want you to remember that most years no one catches, and that's okay. That's why we have seeding day every year, okay? So I don't want you to be disappointed if you don't have a baby this time around."
Lizzy shrugged. "Yeah, yeah, fine. But I'm going to get pregnant today. I can just feel it!"
Joe laughed again: "Now that's the spirit."
Even Kate was grinning softly at her daughter's obvious excitement. "I'm proud of you, Lizzy," she said.
"Me too," Joe added. "In fact, honey, I kind of hope you pick my paper."
A third eye roll from Kate at that, this one the biggest.
--
Martin and Nancy arrived around 15 minutes later, knocking twice in quick succession.
"They're here!" Lizzy cheered, already up and skidding toward the door.
Kate followed closely behind and immediately pulled her brother into a hug.
"Heya, sis," Martin said, grinning.
"Hi, Martin. It's so good to see you."
Lizzy hugged him next. She saw Uncle Martin a few times a year, but it was always nice; she liked him a lot. He was much taller than everyone else in their family -- as they liked to joke: "well, at least we got one" -- but otherwise looked a lot like her mom and, therefore, her.
"You're all grown up, huh, Lizzy?" he said, holding her at arm's length to look at her.
Lizzy just beamed at him.
"It's so wonderful to see you here today," Nancy agreed from behind her husband.
Nancy had dark, rich skin and darker hair, which was braided tightly. She wore glasses, bright red frames that exactly matched the red of her lipstick. But Lizzy found her gaze caught on where Nancy's chest seemed to be threatening to split her shirt open. Her breasts were huge, and as Nancy reached to pull her niece into an embrace, they got pushed together and up, making them look even bigger.
How had she never noticed those before?, she wondered.
Lizzy turned to see that her dad had walked in from the kitchen. He was standing by the side, awaiting his turn for a reunion, but also very clearly staring at the magnificent tits before him. Lizzy smiled.
--
Rob arrived a half hour later, apologizing for the traffic as he entered.
"Hey, dad," Kate greeted. "Glad you made it."
Rob laughed: "Ha, 'course I did. You know I wouldn't miss seeding day. Especially since--" He paused, looking from side to side.
Kate knew exactly who her dad was looking for. "Lizzy!" she called. "Your grandpa's here!"
The teen appeared around the corner, smiling. "Grandpa!"
She had not seen her grandfather in several years, but he was just as she remembered: an unassuming man, dirty blond hair heavily flecked by grey, with a beard that he kept trimmed short.
"There she is!" Rob whooped.
The commotion drew the rest of the family, and they all exchanged hugs and greetings.
"So how are you feeling? Nervous?" Rob asked his granddaughter.
She shrugged lightly. "I'm ready! But, uh, yeah... I'm a little nervous."
He nodded in understanding. "That's very normal, sweetheart. But I can tell you've grown into a lovely woman."
Then something new happened: her grandpa gave her a long, hard look, scanning from the tip of her head down to her feet. Lizzy had never had someone look at her like that, so openly appraising. He licked his lips.
"Are you still a cheerleader, Lizzy?"
"Well, I guess so, but the season's over, and I graduate kind of soon."
"I bet all the boys are sad about that, you know. They're probably going to miss staring at your ass all day."
Joe, standing nearby, tutted at that, though he grinned. "Hey, Rob, remember: the only guy who can stare at Lizzy's ass is me!"
"Is that so? That might change soon," Rob replied.
Lizzy sighed: "Daddy, grandpa, stop it!"
--
Lizzy wasn't sure what happened now. She knew plenty about seeding day: her parents sat her down on her recent birthday and explained the tradition. They told her that the goal was pregnancy, that the partners were random, and that it happened yearly to maximize the chances that one of the oft-taboo pairings would successfully create new life.
And they told her that participation was never mandatory, that no one would think differently, that she could leave at any time. That had gotten an audible scoff out of Lizzy: "What? No! I want to go to seeding day."
None of the conversations contained details about this, though, the awkward in-between. They were all present, but they were all dressed.
As if Rob were reading her mind, he spoke: "Kate, mind if I kick us off?"
Lizzy didn't remember ever seeing her mom giggle like that, shoulders up and cheeks flushed, almost embarrassed. But that was exactly what she saw then, as her mom nodded.
Rob stepped up to his daughter and reached for the hem of her shirt, quickly pulling it over her head and tossing it to the side. Kate wasn't wearing anything underneath the tee, so her chest was bare.
Lizzy's eyes grew wide.
"Lizzy?" she heard, turning to see her dad beside her. "Can I be the first to help you?"
Her heart was pounding. She nodded, and her dad repeated Rob's gesture, throwing Lizzy's shirt aside somewhere. He unclipped her bra after.
"Can I--" Lizzy started, but she found she couldn't speak.
"Would you like to take mine off too?" Joe finished for her.
Lizzy didn't answer, just reached for her dad's top button and began working her way down.
When she finished, Joe spoke again: "Would you like to take my pants off too?"
Lizzy looked around: her mom was tugging down Martin's pants as Rob helped Nancy. She could only see her grandpa's back, but he appeared to be fully undressed already.
"Okay," she said.
She tugged down her father's plaid pajamas without looking. It felt too soon, too much, to see her father's cock.
What if it was hard? What if it Lizzy -- his own daughter -- had done that to him, made him stiffen?
Or worse, almost: what if she hadn't? What if her own family found her unappealing?
So she looked over her dad's shoulder instead, which meant she didn't see -- but instead felt -- her dad's hands pull down her own shorts. She stepped out of them.
The room suddenly seemed to get quiet.
"Well," Kate said, the single word echoing through the silence. A beat, then: "It looks like we're ready to get started."
--
It started with the men sitting in a row on the couch. The women kneeled before them.
Lizzy was in front of Martin. He was already fully hard, and his cock pointed downward a bit, so it was sticking straight at her wide eyes, and she licked her lips.
It was nice: average size but veiny with a thick tip. That was where she started: she licked across his slit, tasting a drip of saltiness on her tongue.
Martin groaned.
Lizzy had never done this before, but she found it came naturally: she grasped her uncle with one hand as her lips closed over him.
She glanced to the side to see her mother lick up her daddy's whole cock. And-- Wow. The motion seemed to take forever, because her daddy's cock was long. Very long.
She was glad she didn't look earlier. That might have scared her.
It stuck almost to his belly button, with a thick patch of hair at the base. Her mom stacked both hands around his length, and there was still plenty left for her to take into her mouth.