In the middle of the bustle of a typical Walton gathering before supper, Jason pulled Erin aside and whispered in her ear.

"Tomorrow morning, after our chores, meet me by the old oak at the crossroads. I've got something to show you!"

Erin whispered back a question, but Jason shook his head. "You'll see," he said, and then shushed as Grandma gathered them at the big table.

Jason and Erin were used to sharing secrets. As a middle boy and middle girl of the Waltons' big family, they got lost in the shuffle a lot, so they clung to each other for support. Both were just about teenagers -- Jason just barely qualifying, Erin almost there. Like all the Waltons, they were tall and rangy, bodies well-conditioned by a life that had no luxuries. The family did for itself, and that included a full complement of chores for every member every day.

Saturday morning's chores, in fact, kept Erin and Jason busy until lunch and even longer -- Erin had to help her mother make a big batch of pies for a church fair the next day; Jason was drafted to help repair a shed down at the family mill.

It wasn't until around 2 o'clock that both of them got reprieves and each hurried off to their familiar meeting place, well away from the prying eyes of the rest of the family.

Erin started closer, so she was already sitting on the limb of the big oak when Jason arrived, out of breath from a scramble down the mountain. She was twisting the hem of her drab print dress, staring idly off into the distance while her slim legs dangled beneath her.

"It's about time you got here," she said with a smile. "I almost thought you forgot. So what's the big secret?"

"It ain't -- isn't here," Jason answered, tugging at her arm to pull her down to the ground. "But it's close."

With Jason leading the way, they tumbled over hillocks and stumbled across fallen branches until they came to a clearing, with a weathered rail fence barring their way. Erin hesitated but Jason leaped the top rail and turned back to help her over as well.

"Jason Walton, just where are we going?" she demanded, refusing to go one step farther.

One glance at the determined look on her freckled face convinced him he had to give her some kind of answer. "This is old man Johnson's place," he said. "I've been coming down here every afternoon about this time for the last week. He's got a couple of horses -- they're usually down at the other end of the field."

"Horses!" Erin snorted. "You brought me all this way to show me horses? We see horses every Sunday at church when the Bartlins come." She turned to go back, but Jason caught her arm.

"No, it's not just the horses -- it's, it's what they're doing. C'mon. It won't take but a little while." He smiled. "Race you."

Jason quickly turned and tore off across the thigh-high field of grain with his sister in close pursuit. Their long, easy strides quickly brought them to the other side of the field. As they reached a stand of elms, Jason slowed down and motioned to Erin to stop. Holding a finger to his lips, he led her around the trees and over the fence again. They followed the fence-line for a short ways; it curved off to their left, enclosing a small pasture ringed by trees, sheltered from the main field. In the middle of the pasture stood a beautiful brown mare.

"Sshhhh," Jason whispered. "It's almost time, I think. Come on, there's a patch of grass right over there. We can watch from there."

"Watch what?" Erin wanted to know, but Jason just shook his head and drew her on. They flopped down onto the sweet- smelling grass, propping their heads on their hands and watching the mare as she slowly grazed.

Then, in a rush of hoofbeats, a well-muscled black stallion came galloping into the pasture. His pounding hooves shook the earth as he raced around the inside of the fence-line again and again; the mare continued to munch calmly.

"Now," Jason said. "I think he's gonna do it now."

The black horse slowed to a trot and made his way out to the center of the field, coming up behind the mare. She turned to look at him and they stood eyeing each other for a minute or so.

"But what..." Erin began, but Jason shushed her.

Then the stallion cantered around behind the mare again. She seemed to brace herself, when suddenly the stallion moved up behind her and rose above her haunches. Erin gasped as she saw a two-foot-long shaft sticking out straight and hard from the stallion's underside. She'd seen enough animals to know that boy horses and dogs and such all had penises, but she'd never seen one so big before. As she watched, the stallion lunged forward and the penis seemed to disappear inside the mare. She gasped again. How could all that fit inside her?

Erin and Jason watched in silence as the stallion rutted at his mate before pulling off and trotting away. They were close enough that Erin could see some kind of white goo around the stallion's penis as he pulled out.

"What were they doing?" she asked her brother.

"I'm not sure," he said, "but I think that's how they make baby horses."

"What? Like that? Oh!" Erin had seen pregnant animals before, and even her own mother; she knew that babies came out of the mother's stomach, and from whispered conversations and snatches of talk among the kids at school, she'd figured out that a man was somehow involved too. But the mechanics of it all had eluded her until now.

"Thanks for bringing me her, Jason," she said fervently. "That was great! But... well, I still think there are some things I don't understand."

"Like what?" Jason hadn't gotten a much better sex education than Erin had, but a week of watching the horses go at it had made him an expert, he thought.

"Well, how does what they did make a baby, exactly?"

"Uh, I'm not sure," Jason said, looking away.

"Oh. Well, how does that big rod thing fit inside the girl horse? It looked way too fat to go in anywhere."

"Uh, I think -- well, I don't know," her brother said quietly.

"Oh. Well... do you know how come that thing was so big? I mean, I've seen boy horses with p-penises, right? But they've never been that big."

Jason's face lit up with a smile. "Oh, I know that one," he said brightly. "It gets big sometimes. All of them do... Even mine!"

Erin reached out a hand and pushed Jason over onto his back. "Oh, go on! Yours doesn't get that big! Where would you put it?" She reached down to his crotch, grabbing at him. They giggled as they wrestled on the ground, rolling over and over, until both were about out of breath. As Erin slipped aside, Jason rolled over to face her.

"Well, silly, of course it doesn't get THAT big," he said. "But it does get bigger than usual. Like... well, like now."

Erin glanced down and noticed that the bulge in his trousers did look more obvious than usual. Still suppressing the last of her giggles, she reached out to touch. Her eyes widened. "Wow, that's really hard," she said. "How did it get that way? Does it hurt?"

"Naw," her brother answered. "Not really. Except it feels kinda cramped. But it's OK."

"Cramped?" Erin asked thoughtfully. "Maybe you should take it out."

Now it was Jason's turn to get wide-eyed. "Take it out?" he squealed. "But..."

"Aw, please, Jason," Erin begged. "I wanna see it. Come on, I've seen you before."

"What? When?"

"Oh, you silly, did you think when we go skinny-dipping at the pond I don't peek around the bushes? Haven't you peeked at me?"

"Well, sometimes," Jason said, shyly. "But... well, you've never seen me like this, I bet."

"Well, then, it's high time. Come on, let me see!" She reached out and slipped a finger into his fly, slipping one of the buttons open. They looked about ready to burst, anyway.

Jason rolled away, but under Erin's soft pleading he soon slipped off his trousers and pulled down his shorts. Even though he was lying on his back, his penis stood straight up, six inches of hard, thick shaft.

Erin crawled over to look more closely. Her warm breath fluttered at the tip of Jason's penis as she turned her head from side to side.

"Can I touch it?"

Jason nodded.

Her touch was soft and gentle, but still it sent a shiver through him. Erin's fingertips slipped up and down the stiff shaft, tracing out the flare of the helmet, the small opening at the tip, the skin stretched smooth down to the base and the floppy sac. Jason winced slightly when Erin experimentally squeezed one of the soft organs she felt inside the sac; she released the pressure quickly.

"Sorry, Jase," she whispered.

"It's OK," her brother said. He couldn't get over how different it felt to have someone else touching him there. Watching the horses the last week, he'd often felt his penis swell, and he'd touched himself, but it had never felt this good. He could go on like this forever, he thought.

But in time Erin sat up, taking her hands away but still eyeing his rod as she spoke.

"Uh, Jason, about that other question I asked..."

"You mean how they make a baby? I just don't know. But I think they have to be old enough or somethin', 'cause I heard Grandpa saying something once about..."

"That's not what I mean," Erin said. "The other question -- about how it fits in?"

"Yeah?"

"Well, I was wondering... Do you think we could try it?"

"You mean -- you mean like they did? Us? Me and you?"

"Yes, well, I mean -- don't you wonder what it's like? When they were doing it, I felt -- kinda -- well, funny -- all warm and tingly. Down by my hole. Like where the boy horse put it in the girl horse. It felt kinda good, but I bet what they did felt better."

Jason didn't take long to answer. "I'd really like to, Erin. Are you sure it's all right?"

"What do you mean?"

"Well, I mean, do you think the horses were brother and sister?"

Erin laughed. "I don't know, but I don't think they cared much!" Jumping to her feet, Erin quickly slipped off her dress and slid down her underpants. She didn't wear anything else; her breasts had developed into noticeable rises on her chest, but money was too scarce to waste on frivolous things like brassieres. Naked now, the young girl shivered slightly as a cool breeze swept through the meadow. As it died down, she got down on all fours, presenting her buttocks to her brother, who had pulled off his shirt and shoes and came up behind her.

Jason felt his penis, already stiff and hard, grow even bigger as he admired his sister's slim body. Bowing to his urges, he moved forward, looming over her. His penis prodded forward, jabbing into her cheeks and then slipping between them.

"Ow!" Erin slumped forward. "Not there, Jason!"

"I'm sorry," he mumbled.

"Oh, it wasn't so bad. Here, let's try again. I'll help." Erin got into position again, this time reaching between her legs to grasp her brother's erect member. He shuffled forward on his knees as she pulled his penis to the entrance of her vagina. It was already slightly wet -- the result of Erin's excitement while watching the animals. But Jason's big penis still couldn't quite penetrate.