18 comments/ 286226 views/ 90 favorites Can't You Knock First? By: citguy00 Jim was a 21 year old average 6 ft blond haired blue-eyed guy who attended the local community college in his town. He was studying to be an athletic trainer since he was interested in playing sports such as football and baseball while in high school. His sister Marilyn was an 18 year old stunning 5'8" blond haired green-eyed beauty who turned the heads of every guy she walked by. She had her share of boyfriends but only few got to go all the way. Jim was no exception to the head turning as he thought about his little sister as a woman and not his sibling. Not a night went by as he thought about his head being between her creamy thighs. He often wondered what Marilyn tasted like as he imagined his tongue piercing her pussy and lapping up each drop of her nectar that leaked out. Jerking his cock he would cream all over his stomach breathing heavily after each session. This is how the story begins. One night during his time alone in his room he had built up to a point of blowing his load thinking about his sister when she came through the door "Jim I'm looking for my CD did you borrow...." she suddenly stopped as she saw her brother stroking his 7 in thick cock. "Oh my gosh....I'm so sorry" she gasped as she tried to turn and leave. Jim's head had popped up and he was trying to stop but it was too late "Marilyn..I ..I" he let out a long moan as he erupted all over himself. Marilyn gasped as she watched his balls tighten and his load squirting. Truth is she loved a man cumming and her brother was no exception at the time. She watched his hard cock continue to gush like a fountain her panties instantly wetting as her pussy swelled and got sensitive from the sight. Jim could not get himself to stop as the beauty of all his masturbation was finally watching him. He quickly imagined Marilyn accepting his load emptying deep into her pussy as her walls would squeeze and massage his long shaft. Finally the orgasm had passed and Jim struggled to cover his cock with his boxers. "Geez Marilyn cant you knock first before barging in" he asked. "Sorry," she said as she snapped out of her cock crazed stare "but I cant find my CD." Jim sighed as he reached over and grabbed it "Here" he said extending his arm. Coming over to get it she couldn't help but look at the lump in his boxers "Wow the girls must be all over you" she said "that there is a gift." Jim blushed and shook his head, "Truth is I haven't even gotten that far. I could cop a feel of the girl but never any farther than that." Even though Jim was a jock he was pretty clumsy with the opposite sex and couldn't get past first base. Marilyn snickered, "So my older brother hasn't had the joy of being inside a woman with that pole between his legs?" Jim shook his head in regret as his cock started to stir from half mast back to full at his sisters words. She strode over towards her older sibling and sat on the edge of his bed, "Well its been about 4 weeks since I got laid and I need a cock desperately. I think I know a cock that could do." With that she leaned down and began to lick up the cum that pooled over his stomach, "Mmmm but first lets get you cleaned up." Jim couldn't believe his eyes as the one he desired in his dreams was licking the very sperm he had always hoped her to take in was licking it off his stomach. "Marilyn," he tried to protest but was too late in stopping watched as her tongue lapped up every drop of cum off of his stomach. "Mmmm very tasty big bro. However, I prefer straight from the tap." She straddled his lower thighs as she started to pull his boxers down revealing his thick man meat. She cooed once she saw his cock stick straight up in the air leaking gooey clear precum from the tip. "That's a good start," she said as her head lowered and her tongue extended lapping up the first bit of that precum. Jim twitched as her hot breath hit the mushroom head and her wet tongue grazing it sent jolts of pleasure through his body. "Marilyn, oh sheesh sis please suck it ....please." Marilyn giggled as she loved the power over men that was given to her as she obliged and closed her mouth over the tip of his cock trying to suck the rest of his love juice from it. Both moaned as they enjoyed the feeling of being purely naughty in this act of incest. Both saw one another not as bro and sis but as man and woman at that moment with feelings of pure lust. Taking his cock deeper into her mouth Marilyn began to bob her head gently applying more suction on his cock as her hand slowly reached down and gently kneaded his balls hoping to get her prize sooner. Jim moaned a little louder than before enjoying his cock being devoured, however, could not go at it alone. "Sis...please let me suck...mm your pussy." Marilyn looked up at him with her lovely green eyes as his cock came out with an audible pop. "Alright big bro." she replied as she turned around on him and pulled off her short shorts and pink thong exposing her creamy mound to him. She was more used to the giving of a blow-job but hardly any return on her part that she enjoyed her brother's willingness to eat her out. "Alright Jimmy if you wish. Ohhh eat my pussy good." She lowered her swollen pussy onto his face as his tongue flicked her sensitive clit bringing a soft purr from his younger sibling. Marilyn quickly resumed her head bobbing of his cock enjoying a slippery wet tongue drilling her pussy. Jim could not seem to grasp the situation as he speared her pussy opening with his tongue finally getting to taste her juices. He again let out a moan as his sister tried to deep-throat his cock her throat clasping his cock like a pussy possibly would. He got a sneaky idea as he read stories on the internet of asshole licking getting a girl off. He looked at her puffy asshole as he ventured upwards and gave it a soft brush of his tongue. Marilyn quickly shot her head off his cock as she drooled onto it. "Wow Jim" she exclaimed "You're such a dirty boy licking your sister's dirty butt hole like that. Do it again." Jim nodded and this time brushed her asshole again this time poking at the opening with his tongue. She started to quiver as she enjoyed the feeling and started to drip like a leaky faucet from her pussy to his face. "Two can play at this game" as she tried to move down and leaned her head into his ass-crack and started to spear her tongue at his hole as he got the idea and started to raise his hips to give her easier access. Both moaned as they continued to drip fluids from the intense feeling of asshole eating. Finally, Jim called out, "sis..I'm gonna cum!" Marilyn moaned as she got an idea and wet her finger with her saliva and started to swirl it around his asshole "Do it bro. Shoot your load into your sisters mouth," she moaned as she stuck the fingertip in. "Oh gawd" he shouted as he started to spurt feeling his sister trying to violate his ass. Marilyn quickly had engulfed his manhood before he started to shoot catching all of his spunk in her warm mouth causing her brother to moan and empty what seemed like endless spurts into it. She reached down and fondled his balls wanting to get every drop he had to offer which he did. After the spurts died down she had lifted her head and swallowed his load eagerly. "Mmmmm good stuff Jimmy." She sat up and turned over as her wet pussy slid over the head of his still rock hard cock. Marilyn snickered as she teased him letting the mushroom head poke into her most forbidden passage and popping it right out. "I think two times isn't good enough for my big bro. Maybe third time's a charm?" she asked as she kept taking in an inch at a time. Jim felt the folds of her pussy squeeze at his cock electing a soft moan of pleasure as she finally went all the way her ass touching his soft sack. Marilyn moaned as she felt full from his hard cock spearing her forbidden passage for siblings. Jim had glanced over at the clock and looked up at Marilyn, "Sis our folks will be home any minute" She snickered at her older brother as she started to ride his pole. "Then we'll have to worry about that when the time comes now wont we?" Moving up and down like a cowgirl, she took his cock hard and deep as it seemed to hit every sensitive spot in her vagina. "Jim, damn your cock is so good. Fuck me...fuck your sister" she moaned loudly as her juices made his cock glisten. Jim's hips moved with hers as she continued to ride him enjoying the feel of his first cunt which was his very sister's. "Damn your tight Mary, man its better than I imagined." he confessed. "Mmmm so big bro always wanted me? Well you have me...ohh gawd I'm gonna cum!" she said as her cunt walls quivered and squeezed his cock. Jim felt a warm gush of fluid on his ballsack as he realized his sister was a juicer as he very imagined her being causing his third orgasm to approach. "Sis I'm gonna cum...quick get off." Marilyn shook her head, "I'm on the pill...fill me up with your forbidden sperm big brother. Imagine you're getting me preggers." she said. The front door of the house opened up, "Kids we're home!" their mother shouted. Both siblings did not care as they were trying to ride to orgasm. "Kids?" their mom asked again as she started to climb the stairs. Their father went back out the front door, "I'll get the rest of the groceries dear," he said. Their mom nodded as she headed towards Jim's room hearing some noises. Opening the door she expected both to just be talking but found something more, "Kids I ....what the!?" she exclaimed. Marilyn looked behind her as she gasped out, "Hi mom....oh my gawd Jim...shoot it!" not caring her mother was there seeing her. Jim looked over and saw his mom, "Oh shit mom...I'm cumming!" he shouted as he starting to erupt his cum into his sister's hot cunt. Their mother stood there watching her sons cock expand and pulsate emptying its contents into her daughter's pussy. She couldn't help but stare at it like a train wreck as she could not believe her innocent children we're like lovers looking for a sexual release. Marilyn snickered as she lowered her pussy to catch the cum shooting from her brother's manhood knowing her mother was there watching it. She rose up as his cock popped out and her pussy leaking his very cum he just shot into her. "Oh Jim that was a good fuck" she said as she squeezed her pussy muscles making it leak. "Looks like mom liked watching it. Look mom its your sons cum...mmm its so warm...ohh i can feel his sperm wiggling its way in my pussy. We'll be down in a minute but I need a little more cock." Marilyn grasped the cum coated shaft of her brother and slid her pussy back down on it riding slowly. Their mom quickly shut the door and started to breathe heavily excited but yet ashamed at her kids. Can't You Knock First? Ch. 02 Crystal, a mother who was at the age of 45, lived a normal life. She had a great marriage to her husband Jeff who was a loyal lover and a great romp in bed. After having both of her kids, she tried to stay in shape to keep her 5' 5" frame in tight condition. Her dark brown locks and her sparkling green eyes added to her features that gave every grown teenager and man a hard boner as she walked past. On the day of the event she and her husband decided they needed to restock on groceries and proceeded to go to the store. She smiled knowing both of her children were the most innocent beings on the planet. After filling up their cart and loading up the car, they drove back home to unload the food they had just bought. After entering the front door she called back to her husband, "Jeff go ahead and start I'll have the kids help." "OK honey," he replied as he opened the trunk. "Kids we're home!" Receiving no reply she began to climb the stairs. She kept smiling to herself knowing that both of them were such sweet children and would help at a moment's notice. Reaching the hallway she had heard some commotion coming from Jim's bedroom. She figured they must be talking about something and started towards his room. The sounds became more distinct grunts and slapping of something wet. Shrugging it off she opened the door to Jim's room, "Kids I...what the?!" she said. Marilyn looked behind her as she gasped out, "Hi mom....oh my gawd Jim...shoot it!" not caring her mother was there seeing her. Jim looked over and saw his mom, "Oh shit mom...I'm cumming!" he shouted as he starting to erupt his cum into his sister's hot cunt. Their mother stood there watching her sons cock expand and pulsate emptying its contents into her daughter's pussy. She couldn't help but stare at it like a train wreck as she could not believe her innocent children we're like lovers looking for a sexual release. Marilyn snickered as she lowered her pussy to catch the cum shooting from her brother's manhood knowing her mother was there watching it. She rose up as his cock popped out and her pussy leaking his very cum he just shot into her. "Oh Jim that was a good fuck," she said as she squeezed her pussy muscles making it leak. "Looks like mom liked watching it." Look mom its your sons cum...mm its so warm...oh i can feel his sperm wiggling its way in my pussy." We'll be down in a minute but I need a little more cock." Marilyn grasped the cum coated shaft of her brother and slid her pussy back down on it riding slowly. Their mom quickly shut the door and started to breathe heavily, excited, but yet ashamed at her kids. She couldn't believe that they were involving themselves in an incestuous way. The innocence that was within their family was now shattering like broken glass. Trying to pick up the pieces, she went towards their bedroom and sat on the edge of the bed forgetting that she had left her husband all alone to unload the groceries. She shook her head as she denied that both her son and daughter were having sex right in front of her not caring that she was watching it. A slight tingle traced its way towards her breast as she started to softly massage it feeling that tingle work its way south. Moving her hand down towards her crotch she gave it just the slightest touch as she let out a sharp gasp. She was somehow turned on by the fact of catching her own flesh and blood in the act of mating. Pulling her hand away, she cursed herself for having these thoughts and got up quickly. Crystal couldn't let her husband find out about this act or he would surely kick them both out. She composed herself and went downstairs and met him at the front door as he was still carrying the load. "So are they coming?" he asked. "They were playing a game," she quickly replied. "They'll be down in a minute." Jeff laughed as he could understand this generation and the video game addiction. "Well I hope they get here soon I'm almost done." The door to Jim's room opened up as their son came down fully clothed in his baggy blue jeans and a white t-shirt. "Sorry about that dad, here let me help," he said taking the bag from his dad's hand. "Thanks son," said Jeff as he watched his boy carry the bag into the kitchen. "Where's your sister?" Jeff looked over his shoulder, "She said she wasn't feeling too good so she went to lay down on my bed." His father nodded, "Well I hate to hear that." "Hun why don't you go check on her," he said. Crystal felt a little uneasy but spoke up, "Alright. Don't you guys work too hard." Both men laughed as they each went outside to get the rest of the groceries. On her brother's bed Marilyn laid there on her back stark naked. She sighed at the good screw with Jim reliving every stroke he pushed up into her. Still feeling horny, she slipped her right index finger into her quivering pussy feeling the mix of both of their cum all over inside of it. Moaning, she moved the finger in and out like a little cock that was trying to scratch the very burning itch it had inside of it. Removing that finger she cooed softly and brought it to her mouth tasting it. "Yummy," she said to herself as she brought it back down to her pussy. As she did this a slight trickle of the white liquid had oozed its way down her ass crack and over her puckered hole which made Marilyn shiver. Loving the feeling of it, she uses her middle finger to wipe the cum all around her asshole trying to lube it up. She let out a audible grunt as her ass tried to reject the intruder. She kept trying to work the rest of her finger in and noticed that the door knob to her room had turned slowly. At this point she did not care who came in as she kept forcing her finger into her ass. Crystal had climbed back up the stairs wanting to at least get a few words in to what they thought they were doing. Approaching the door to her son's room she had heard her grunt and figured something must be wrong. Opening the door slowly, she starts to look inside to see if what they did had somehow hurt her. Again, she was caught by surprise seeing her daughter having her middle finger up her asshole. "Marilyn!' she said, "For the love of God what are you doing?" Her daughter looked up at her and just grunted, "Mom...unghh don't you knock?' She let out a sharp gasp of air as 3/4 of her finger was now inserted into her ass. "Ahhh," she sighed at the feeling. Crystal just couldn't believe that even after their daughter had just broke a sinful taboo that now she was trying to masturbate even with her and the family all home. She blushed at the embarrassment as she stepped inside the door and closed it behind her. "Young lady we need to talk," she said. Marilyn grunted one more time as she got the rest of her left middle finger inside of her asshole, "Ahhh that feels so good." Leaving it there she smirks up at her mom, "OK lets talk." Her mom tried so hard to throw out any kind of feelings that she was a little turned on by her daughter's boldness. "For the love of....Marilyn don't do that in front of me" Moving the digit in and out of her ass she giggled, "Why not...I'm a woman after all." "Don't be such a prude...ohhh mom...I feel so full," she started to moan and pushed deeper each time she came out. Crystal feeling flustered and frustrated moved over to her daughter and grasped her hand pulling her finger out of her butthole. "Why did you do that with Jim?" she asked. Marilyn sighed at now feeling empty, "Aww mom I was getting so close," she sighed. "I don't know...I was feeling horny and Jim was just jerking his thing when I came in to find my CD. I couldn't help myself. One thing led to another and that's where you came in." Shaking her head, her mom just couldn't believe the events that had just transpired just minutes ago. "Hes your brother Marilyn, you cant just go off having sex with your sibling. Its incest and its illegal in most states." Looking at the sight of her daughter she just sighed, "What would your father say?" Marilyn snickered as she looked on at her mom, "Oh mom you know you wont tell dad. He'll be so ashamed and just feel so disappointed now wont he?' Crystal gasped at the thought and started to hang her head as she knew Marilyn had a point. How could she face her husband and admit that she found their kids fucking each other. "You cant do this sweetie. It's just wrong each way you look at it." Marilyn laughed softly, "Well in my opinion he's a guy and I'm a girl. Its bound to happen no matter what. You better get back downstairs before dad comes up here finding me with all this cum dripping out of me." She slowly ran her hand back down towards her mound and started to use her finger to stroke her clit forcing a little glob of cum out of her vagina. "Mm besides mom don't you like daddy's cum in you just oozing slowly out. What a rush it is." Moving her hand down more she uses her middle finger to glide inside of her ass still feeling slick from Jim's semen mix earlier. "I bet Jim gets his big cock from daddy." Crystal got up shaky and defeated. She had hoped to make her daughter feel sorry for her acts of infidelity, but in turn she left feeling guilty and tingly from the excitement of watching her daughter masturbate. Their daughter forces her finger in one smooth motion up her ass, "Unnghh don't worry mom...ahhh...its our...secret ...yeah!" Closing the door behind her Crystal wipes her eyes with one hand as the other trails southward again touching her tingling pussy. What was she to do now?