The two boys sat on their beds in a room decorated with model planes and toy cars and one rather worn-out teddy bear.

"At least Bobby's away at summer camp, so it's just the two of us," Peter said.

Greg nodded in agreement. "Yeah. But it's worse for me, Pete. If Dad hadn't gotten married again, I'd be in my own room still. I'm too old to room with you kids. You've got a couple of years yet before you can complain."

"Oh, yeah? Havin' to share my bedroom with my dumb little brother and you? And having those girls around the house all the time? I wish Dad had just stayed single. Mom would never had made us all share one room. Why can't we just buy a bigger house? Or build one? He's an architect, isn't he?"

"But not a pretty good one," Greg said. "What kind of architect makes six kids share one bathroom?"

Peter smiled. "Then I'm glad he's no good. That keyhole is the only good thing about having the girls in here."

"Yeah, you're right. But I'm gettin' too old to whack off just watching. I hate having to wait for Marcia or Jan to get out of the bathroom again before I can go in and wash off."

"But what can we do about it?"

Greg was about to reply when they heard a noise in the bathroom. The boys held their breath, straining to hear. It was after 9 in the evening, the girls' turn to use the bathroom. Over the last few months they'd gotten used to the noises each one made: Cindy, the smallest, always made the toilet squeak when she crawled on top, and usually knocked over the toothpaste tube at least once. Jan, the middle girl, was really quiet; even when she peed, you could hardly hear the splash. They'd already heard Cindy's bumbling and Jan's timid "swoosh," but sometimes one of them snuck back in before their oldest sister got her chance.

They heard the clatter of bottles bumping together. That had to be Marcia, the oldest. She always wore makeup during the day and smeared it off at night. The boys looked at each other, huge grins on their faces. "Well, I guess whacking off one more night won't hurt," Peter said.

They tiptoed up to the door and silently played scissors, paper, stone to see who went first. Greg won, so he kneeled down and put one eye up to the keyhole.

In the narrow bathroom, Marcia was standing at the sink, wearing only a bra and panties, both in demure white. She wasn't as big as the women in the Playboys Greg had hidden under his bed, but she was big enough to need a bra, at least. She was tall for her age, and slim but not skinny: she had curves in all the right places. Her long blond hair fell straight down onto her shoulders, framing an oval face that was pretty enough to have several guys at school asking Greg to set them up with his new step-sister. Fat chance, though; Marcia was a snooty bitch, Greg thought; she barely talked to him, let alone his friends.

His train of thought was derailed by Peter's poke from behind. "Hey, it's my turn!"

The boys changed places. Peter knelt before the keyhole and slipped his slacks and underpants down to his knees. His hand hovered over his cock, but he didn't touch it and it stayed soft. "She's not naked yet," he said with a frown. Marcia was posing in front of the mirror now, holding her hair up in a bun, then pulling it into a ponytail. Finally she let it fall back and put her hands behind her back, reaching for the snap of her bra.

Peter was about to start stroking when Greg pushed him out of the way. "Time's up," the older boy said.

As Greg watched, Marcia pulled the bra off and tossed it on the toilet tank. Her breasts were even whiter than the rest of her creamy body, making her dark nipples and the circles around them stand out sharply. Marcia posed in front of the mirror again, cupping the tits and pushing them together to form cleavage. Greg's cock was out of his pants and he was rubbing himself slowly. He saw Marcia turn away, looking at her tits in profile. They stood out nicely from her chest, like smoothly rounded hills.

That was all Greg got to see; Peter pushed in and took up the spot at the keyhole. As he watched, Marcia pulled her panties down to the floor and stepped out of them. Peter had one hand on the doorknob and the other on his knob; for a second he forgot which was which and rattled the doorknob. Marcia looked up quickly, but Peter was quiet. Marcia then kicked the panties off. Peter's stroking grew faster as he saw the small patch of hair that bloomed like a flower just above her cunt, leaving the the lips fully exposed.

He saw her pull aside the shower curtain and turn on the water, then quickly toss a towel onto the toilet seat and step into the shower, drawing the curtain behind her. Greg put a hand on Peter's shoulder.

"There's nothing to see, she's in the shower now," Peter said, shrugging off the touch. "Leave me alone, I want to finish."

"Yeah, she's probably standing right in front of the keyhole," Greg whispered back. As the boys struggled, Peter's hand pushed on the doorknob again. "SSssshhh!" Greg hissed, and he put a hand on top of Peter's. Their hands slipped on the knob and it twisted; as they pulled away the door began to open. Hastily, they eased it closed. "That was close," Peter said.

Then the boys looked straight at each other. And at the door. And at each other again. "Didn't she lock the door?" Greg asked. "I thought you saw her," Peter said.

Without saying another word, both brothers stripped to the skin. As Greg opened the bathroom door, he turned back to Peter and whispered very quietly. "Just follow my lead."

They tiptoed in, taking long strides to reach from one floor mat to the next. At the near end of the tub, by the faucets, Greg motioned Peter to stop and wait. The older boy continued across to the far end of the bathroom, crawling along the floor so Marcia couldn't see his outline through the shower curtain. He locked the door to the girls' room, then crept back to the end of the tub.

They could make out a blurry image of Marcia's body through the translucent curtain as she soaped herself up, rubbing all over. Finally Marcia put the bar of soap down on the edge of the tub, just inches away from Greg. As she stepped back to rinse, Greg reached out and tipped the soap into the tub, where it fell with a clatter. As Marcia bent down to retrieve it, Greg pointed at Peter.

In a flash, Peter slipped through the shower curtain and stepped in behind his step-sister. Marcia straightened up with a jerk, but before she could turn around Greg stepped in front of her. While she was staring in shock, Peter grabbed her from behind, one hand over her mouth and the other around her waist.

Marcia tried to squirm out of his grasp. Peter's hand slipped easily on her sleek, soapy skin. Greg managed to take hold of her hands, but Marcia continued to struggle. Peter's left hand was clapped firmly on her mouth, but his right was sliding up and down. When Marcia tried to slump away, his hand rubbed across her breast. A jolt went through his body as he felt her hard nipple underneath his fingers. Her butt was sliding back and forth in his crotch, and he could feel his dick growing harder and bigger. The water continued to cascade over them. Peter started to lose his grip and she pressed forward. Peter tried for a better grasp and found himself clutching a handful of curly hair, then his hand slipped again and he felt her pussy lips. He moved in closer to stop her squirming and his cock settled into the valley of her butt. It fit snugly, and the water pouring down quickly washed away the soap, allowing the tight squeeze to create friction that made Peter's rod bigger and harder.

While Peter was struggling, Greg had pulled Marcia's hands up above her head and he was trying to kiss her tits. Marcia twisted to one side, allowing the water to hit Greg full in the face. He fell back, hitting the back wall of the shower and sliding down until he was sitting on the edge of the tub, Marcia's hands slipping out of his grasp.

In that same second, Peter's fingers slipped past the pussy lips and popped into Marcia's cunt, hot and soaking wet from the shower and their struggle.

Marcia leaped away in shock, pulling Peter's hand from her crotch. But as she landed, her feet began to slip out from under her and she fell forward. Greg reached up to catch her and she managed to regain her footing, but when Greg grabbed her tits in both hands she staggered back, still crouched over -- and impaled her cunt on Peter's rigid cock. As Greg's hands slid off her tits, Marcia slipped a bit and her head dropped down into his lap. She opened her mouth to scream but Greg's rock-hard dick slipped in.

Except for the swoosh of the shower, there was no sound or movement for several shocked seconds. Then nature took over.

Peter began to stroke in and out of his step-sister's tight cunt, staring in fascination as her pussy lips stretched to take him in. The smooth white globes of her ass stared back at him. Marcia was still squirming, but that only made the feeling better.

Greg reached up to take her head in his hands and pushed her down onto his cock. He felt the tip slide up her tongue as it scraped along the rough top of her mouth. As it hit the back of her throat, she recoiled -- slamming Peter's cock through her maidenhead. She let out a long, low sigh.

Greg's dick was still inside her lips, and the vibration of her sigh made it thicken even more. He once again took her head in his hands, and this time she didn't resist. Forming her lips into a pursed "O", she sucked on his rod as she slowly knelt down, careful to keep Peter's peter inside her as he knelt behind her. With one hand on the tub's bottom for balance, Marcia reached up with her right and encircled the base of Greg's dick, rubbing up and down the part her lips couldn't reach.

Peter returned to his stroking as well, now able to push all the way inside her hot tunnel. Soon the three fell into a rhythm, with Marcia first heaving back onto Peter's cock and then leaning forward to take Greg's cock deep into her mouth.

"Oh, God, Marcia," Peter moaned, "you're so damn tight. God, you make my cock feel so good."

"Yeah, and you suck great, too... Sis," Greg said quietly.

Marcia looked up at him, her eyes wide. It was the first time he'd called her "sister," the first time he hadn't treated her as an outsider in his home. She pulled back from his cock and smiled. "Mmmm, thanks. With two cocks like this around, I'm really glad I'm in the family. Now shut up and stick that cock back in my mouth."

They went back at it as steam curled over the top of the shower curtain and water poured off their bodies. Peter pounded away at her pussy, ramming his cock in and out. He couldn't get over how different the sensation was from rubbing himself; Marcia's cunt fit like a second skin, tight but at the same time almost pillowy soft. Every once in awhile he pulled all the way out, just for the joy of slipping slowly back in again and feeling her lips slide around the head of his dick. His hands roamed over her body, caressing her. Tentatively, he slid a finger down the crack of her butt and slipped it into her asshole; Marcia wiggled in acceptance. As he pushed the finger in and out, he almost could feel his own cock stretching her cunt tight against it.

Greg was lost in his own excitement as he saw his sister's head bob up and down on his cock. Once she pulled out again and he started to say something, but she just pulled up his rod and began to lick it on the bottom, from the base to the tip. A shiver ran down his spine. She tenderly cupped his sac in her hand and licked it. When she popped him back into her mouth, he reached down and grabbed her tits, taking a nipple in each hand and gently squeezing. Marcia's hand on his cock began to speed up and Greg began to groan. His breath came in short gasps and at last he moaned "I'm... I'm coming!" He felt the jism boil out of his balls and shoot through his cock to explode into his young step-sister's mouth. Marcia swallowed it all in a few gulps and pulled back, wiping the last few drips away with a finger and then sucking the finger clean.

"Hey, Peter, how are you doing?" she called back. The younger boy was still pumping away. In answer, he slammed his cock forward as hard as he could. "Unngggh!" Marcia grunted in pleasure. "Slam it into me, Peter! Ride me like a fucking dog! Yes! Yes!" Her dirty talk sent Peter over the edge. He spurted deep within her as Marcia's body began to be racked with contractions. Greg bent down and kissed her hard, their tongues wrestling together, as her butt wiggled furiously and Peter held on as tightly as he could.