Note: This story was dynamically reformatted for online reading convenience. As Ceri swam she thought about what had happened this morning. She had of course gone into the bedroom with her bikini on on purpose. She had known that her dad and future mum were fucking and she had wanted to distrub them. When the opportunity had come up to show her dad her body near naked she had leapt on it. It was a chance that she had not been able to pass up. Especially since there was a good chance that he had been buried in Char's teenaged body right as he looked at her. And since both girls looked so alike Ceri knew that her dad would have been thinking about fucking her too. That brought back memories of yesterday, and how good his dick had felt in her pussy. Incest, wow! Even if he had not realised it was her. Even if he had gotten the two of them mixed up. He had now fucked his daughter and Ceri knew it would not be the last time. She would use any occasion she could to play with her almost twin like similarity with Char. She was just glad that the two of them had sex often enough that her parents would not count up how many times they had done it in a day! The cool water was carressing her body as the youngster pulled herself through it. It set her to tingling, and the thoughts of the hot sex yesteday made her pussy join in. As she turned she pushed over onto her back thinking that maybe she could get some release from the tension. If she just slipped her hand down between her legs and frigged a little no-one would know surely...? "Hi sis!" Came the shout. Ceri cursed. "Hi bro!" She shouted and smiled, sitting up. She began to tread water, watching her brother walk around the side of the pool. He had obviously been watching her for a little while and, much to her amusement, she could see that he had a tight thick pole in the front of his baggy swimshorts. He was trying to walk to cover it but Ceri had a sixth sense for such things. She knew he had it just as she had known about her dad's last night. She enjoyed watching it bob as he moved. Eventually he reach a sunlounger and sat down. Reclining her began to read a book. Ceri swam over to him. She rested her chin on her hands and watched him for a little while. There were two reasons for this. First her brother looked good without a shirt on. Second she could see right up his swimshorts to his cock from this angle. She lay there for a bit simply being still. He was still very stiff and she was enjoying the view. She thought about the other day with the photos and how she had been about to give him a BJ when dad came home. The thought made her pussy even more excited. Darn it, she needed sex again and soon. She began to wonder how she was going to get it. Just no opportunity would present itself with her brother. "What you looking at?" Asked Jim, looking down at her from behind his pages. "Oh..." Ceri grinned, "Just enjoying the view." Jim caught a look at his own state and blushed. He sat up and pushed his shorts down around his raging hardon. "Well don't, you're my sister." "You didn't complain Friday night did you? Forgot I was your sister then." "Yeah, but that was wrong, Ceri." She pushed up from the edge of the pool and lifted herself out with her arms. Standing there, dripping, in her tight little bikini, she put her hands on her hips. "Wrong? Why?" Jim looked at her and gulped. "Because you're my sister!" Ceri shook her long strawberry blond hair. "So when you're looking at me you're thinking thoughts about your sister. Or are you just seeing a beautiful woman who is turning you on?" "Both! Neither! Oh Ceri, let's just stop this! It's not right!" "What do you not like, Jim? Is it my boobs?" She put her hands under them, lifting them as though to offer them to him. "Or my butt?" She turned and wiggled her tight bottom at him, stroking it with her forefingers. Jim did not reply. He simply sat there, mouth open, not even bothering to try to cover his straining dick anymore. Confidently the teen strode over to him. She knew what she wanted and was going to go for it. The thing with her father yesteday had taught her well. If you wanted sex you had to get it. No matter who it was with. If she could willingly shag her father then she could darn well make sure her brother got some too. Kneeling, she grasped the top of his shorts and pulled them down, so that his cock popped out. She loved it so much. She placed her hand around it and examined it. Felt the thickness and weight and warmth. He simply lay there gasping and not believing what she was doing. Again. Jim groaned as his sister's hand closed around his shaft just below the head. Her fingers slipped around his wanting meat, and he could feel her breath on his bulging head. Jim loved blowjobs, had decided that as soon as Charlotte had started hers the day before. "No!" He moaned. "You mouth says no but I can't hear it over your cock, bro. What a beautiful cock you have..." With this the horny teenager slipped her lips over the side of his shaft and sucked, sending waves of pleasure up to Jim's fevered mind. She knew what she was doing, oh did she know... Her tongue was flickering over his shaft next. The girl had advanced to licking his balls now, pumping his shaft with her hand. As he looked down and watched, her bright head moved up his horny dickmeat until her lips were poised at the head. Looking up into his eyes, his sister deep throated him in one smooth moment. As he felt his uncircumcised dick hit the back of her throat Jim knew he would never find another cocksucker like his older sister. "Yessssss... suck me, sis!" Moaning around his cock, Ceri went to work. Her mind was fevered with the scent of her brother's pulsing dick. She loved the way he felt between her lips, and the taste that came to her tongue. She wanted to taste him desperately, wondering if there would be any better spunk in the world than her own brother's. She bobbed her head faster and faster, driving him down her throat while she looked up with begging eyes. He had forgotten who she was now and everything wrong about it. His eyes seemed to be crawling all over her, searching each inch of her sexy creamy body. Reaching up with her hands Ceri pulled her bikini top up around he rshoudlers, exposing her young breasts. As the two small globes, topped by pink nipples, popped into view Jim gasped. His sister had the best rack he had ever seen. As she rocked backwards and forwards they moved with her supply, without a hint of sag. Taking her mouth from his cock, Ceri rumbled. "Give me your cum bro. I want to taste it now. I'm ready. Pleeeeeeeeeeeeeeeease..." Then she returned with doubled efforts to his suffering pole, mining it like a pro. Her hand went between his legs and she played with his big heavy balls, then stroked back and tickled his asscrack. His back arched with pleasure at this so Ceri pushed her finger in and wriggled into the tightness of his pucker. JIm yelled out so loud the neighbours would probably hear. Not that Ceri would care at this point. She had this great dick down her hungry mouth. She had known boys before who loved to have their anus tickled and she had no problems doing it. Especially when she found out what it did to Jim. Jim could hold on no longer and felt his sperm jet down the teen's throat, listening to her gulp as he filled her with his semen. She seemed determined to get more and more out of him, and Jim could only cry out and thrust, holding her head with both hands. He had cum down his sister's throat! He was jetting spermy cream right into her waiting gullet and she was swallowing it! Ceri pulled from him and licked her lips, caughting an escaped ribbon of cum with her finger. Licking it, she marvelled at the perfect taste of his jism. She knew she would be going back for more now this taboo was unlocked. "Thank you for the present, bro." She murmured, patting his cock. "My pleasure, sis, my pleasure..." CLAP CLAP CLAP. The two turned and gasped. Charlotte stood on the edge of the pool. She had dressed in the bikini Ceri had worn yesterday. As they watched she dived into the water. Ceri, shocked, stood and ran into the house. She did not even stop to do up her bikini top. Her young breasts shivered all the way. Jim pulled up his shorts and sat back, trying to think of something to say. He was scared. Very scared. What they had just done was so very wrong. Char giving him a BJ had been one thing. She was not his mother yet and was not even genetically related. Char was his sister. One half the same as him. That was incest. How much trouble would he be in now? Char swam half a length under water. Then she surfaced and pushed to the side of the pool. Giving the teen one hot look, she winked and then pushed away on her back...