Mark was lying on his bed, wearing only his jockey shorts, waiting for Stacy to come. He knew she'd be there, as soon as she was sure the adults were asleep. Finally the door opened quietly, and Stacy came bouncing in, wearing a short nightgown that hardly covered her ass.
She ran over to him and bounced onto the bed, giving him a quick hug. "Oh, Mark," she exclaimed, "I can hardly wait to tell you about my day."
"Okay, okay," he laughed, "but keep it down. We don't want to wake them up. So what happened at the beach? Did you get it on with Uncle Bill?"
Stacy nodded gleefully. "I finally did it," she said. "It wasn't easy. Man, he was protesting right up to the last second, even when I sucked his cock, but he finally gave in. I've got him now."
"Far out," said Mark. "And I've got good news, too. I finally got into Karen. She was just like him, protesting all the way, but when I got my cock into her, she changed her tune. Looks like we've succeeded, little sister. We won't have to sneak out at night to look for fun if we don't want to. We can have it right here."
Stacy clapped her hands. "Oh, Mark, I'm so happy," she said. "But is Karen a good lay?"
"Yeah, she's fantastic," Mark said, sighing at the memory. "And she's gonna get better. She has a lot of inhibitions to lose, but she digs it. What about Bill? Is he any good?"
Stacy sighed, too. "Oh, wow, yeah," she said. "He's got the biggest cock I ever saw. In fact I get horny just thinking about it."
"I'm horny, too," said Mark. "I was gonna make it with Karen a second time, but you guys came home. Listen, you wanta play our game?"
Stacy nodded eagerly. "Yes, that's a good idea, Mark," she said. "I'm really up for it."
Brother and sister quickly took off their clothes.
Mark and Stacy had a special game that had begun a long time ago when they were just children. It started during a brief period when their mother had to work nights, leaving them alone in the apartment. There was plenty of food, the lock was secure, and they were in no danger, but the two kids sometimes felt spooky without their mother.
So Stacy got into the habit of crawling into her brother's bed.
At first it was just for company. The kids felt safe and secure together. Then after a couple of weeks they started exploring each other's body, curious about the difference between boys and girls. They discovered that touching each other, especially between the legs, was a lot of fun.
They refined their play, telling each other what they liked best, and then one memorable night they accidentally made each other climax. It was the first time for both of them. They enjoyed it so much that they made it into a permanent game.
Their mother started working days again and staying home at night, and she said they couldn't sleep together, that they were getting too old for that. So they just waited till she went to sleep. As they grew into adolescence, they invented more and more crazy things to do. But so far they hadn't fucked. In fact, it didn't occur to them. That was something they did with other people. Their own private game consisted of delicious touching, nothing more.
"Move over," Stacy giggled. "You're taking the whole bed."
"Okay, greedy," Mark laughed.
They had pulled the covers down so they could see each other. They loved each other's bodies. Mark thought his sister was the prettiest girl he'd ever seen, and Stacy thought her big brother had a really super body.
They lay down side by side and began touching each other. Mark began by fondling and squeezing his sister's plump round tits, something he knew she liked. Stacy seized her brother's limp little prick and playfully pumped it.
"So ol' Bill's got the biggest dick you ever saw, huh?" Mark said, grinning. "Is it bigger than mine?"
"I'm afraid so big brother," said Stacy, fondly petting his soft sleepy prick. "But you've got some growing to do yet. You might catch up with him."
Mark happily fondled his sister's firm little jugs. "Well, my feelings are hurt," he teased. "I'm just gonna have to tell you that Karen's tits are a lot bigger than yours. Man, they're like mountains."
"I know," Stacy sighed. "I sure hope mine get bigger."
"Aw, I was just kidding, Sis," said Mark. "Yours are fine, the nicest I've ever seen. Anyhow, if they were any bigger, I couldn't get 'em in my mouth, and that'd be a drag."
Stacy giggled, but her eyes were hot and glowing. "Hey, Mark," she said huskily, "why don't you just do that? Suck my tits, I mean. I could really get off on that."
"Okay," said Mark, "but you gotta do something nice for me, too."
"Oh, I will," Stacy said impishly. "You better believe I will."
Mark brought his mouth down to one of his sister's pretty pink nipples and tickled it teasingly with his tongue. Stacy squealed with delight.
"Hey, not so noisy, okay?" Mark said fondly. "The shit would really hit the fan if they found us like this."
Stacy sighed. "Yes, dammit," she said. "Wow, those two are really a drag."
"Not for long," said Mark. "We're working on them. Now I'm going back to working on you… but keep the noise down."
He popped his mouth onto his sister's perky little nipple and began to suck it leisurely. He felt the soft tip of her breast slowly harden in his mouth, getting erect and throbbing. Stacy almost squealed again but managed to convert it to a prolonged sigh of pleasure.
Mark felt his sister's little hot hand closing around his flaccid pink balls. He hummed happily to himself. He really liked it when Stacy played with his nut sacs, because she knew just what to do. He felt hot excitement as she began to knead and massage the soft sensitive bags.
Brother and sister lay side by side, naked, a beautifully matched couple with their deeply tanned trim bodies and thick platinum hair. Mark's head bobbed gently over his sister's ripe round tit, and Stacy's hand moved rhythmically around her brother's fat young balls. A stranger might have thought they were lovers.
But they had never really been lovers, and Mark was just now beginning to wonder why. Somehow in all the years they'd played together in bed, they'd never thought of fucking. They'd done everything else but that. It made Mark chuckle.
"What's so funny?" said Stacy.
Mark drew his mouth off her wet erect nipple. "Aw, I was just thinking," he said. "It seems weird that you and I never ball each other."
Stacy blushed slightly. She wasn't one for blushing, but Mark's thought had occurred to her lately, too. It did seem kind of strange, and yet…
"Well, but Mark, we're brother and sister," she said. "It wouldn't be quite right, would it?"
He stared at her. "You've been listening to that bullshit Bill and Karen put out," he said, "that crap about incest."
"No, I haven't," Stacy protested. "I mean, I don't believe it's necessarily wrong. It just seems kind of funny, that's all. I mean, my own brother…"
"Oh, Christ," Mark said scornfully. "Okay, if it bothers you, let's just forget it."
It did bother Stacy, but she didn't know why. Idly she reversed her position beside Mark so she could lick his balls and he could play with her pussy. It was one of their favorite things. Usually they made each other come that way. But now Stacy was thinking maybe her brother had a point.
Mark eyed the pretty little puff of platinum fur over his sister's muff. It was the loveliest muff he'd ever seen, and he got aroused just looking at it. He quickly parted the blonde furry lips and exposed the tiny red bump df her clit. His tongue snaked out to tickle it.
"Ummm, yeah, Mark," Stacy sighed, "that's good…"
She returned the favor by sticking out her dainty pink tongue to lap and tease his pretty pale cock. She'd seen a lot of cocks in her short life, but she still thought her brother's prick was the most handsome and exciting. She loved to lick and taste it.