Donnie is a nerd who experiments with a chemical compound that is supposed to make his cock grow. Things go wrong and he gets a painful erection that won't go away until he cums. Making himself cum cum turns into a monumental problem and he has to ask his big sister for help.
EVERYONE IN THIS STORY IS AT LEAST EIGHTEEN YEARS OLD OR OLDER.
Donnie Hamilton is the typical annoying teenaged little brother. There was just two years difference in the ages of him and his big sister, Lucy. The immature way he acted, one would think there was much more of an age gap. She tolerated Donnie’s juvenile behavior because she loved him. She learned to put up with his pranks because she understood Donnie was going through puberty and was beginning to have an interest in girls. She also knew he was too young and inexperienced to understand why he was attracted to the opposite sex. Every time she had her girlfriends to their home for a sleepover, he acted up.
Lucy is a beautiful young girl with golden hair, crystal blue eyes, and luscious full lips. Donnie is the exact opposite of his sister. He is a tall, gangly boy with freckles and large feet that made him uncoordinated and unsuited for sports or anything that required agility. Donnie had very few friends. Lucy, on the other hand, was one of the most popular girls in school. Lucy was a boy magnet, and boys would fall all over themselves to be near her. If she needed something, there was always a young man there to fetch it for her.
Lucy was captain of her cheerleader squad, president of her senior class, and was elected homecoming queen two years in a row. Donnie wasn't exactly ugly, but he seemed to repel most girls with his unpredictable conduct and unappealing appearances. He was a bit of a nerd who enjoyed science and computers.
Donnie had a chemistry set and often found chemical formulas on the internet to use with experiments. One of his favorites was hydrogen sulfide (rotten egg gas) that he released one night when his sister had a slumber party. Lucy's bedroom smelled like farts the rest of the night, and the girls had to move their slumber party down to the den.
By the time Donnie was eighteen and a senior in high school, he was still a virgin and didn’t have a girlfriend. He had started to notice tits but had only seen naked ones on the internet so far. The only thing Donnie knew about sex, he had learned from porn sites. He still didn’t know how to relate to the opposite sex successfully. He was somewhat like a ten-year-old boy who chased and pulled the hair of girls he was attracted to on the playground. He knew it was time to grow up and learn to act like a sexually experienced teenager.
Donnie was desperate to get a girlfriend and lose his virginity, so he checked his porn sites to find out what girls wanted in a boyfriend. He noticed that all the men on the porn sites had ten to twelve-inch cocks. Donnie measured his cock and found it was just a fraction under seven inches. He had to find a way to grow a long cock. He searched the internet for a chemical formula that promised a bigger, harder cock and also claimed it would stay hard until a girlfriend was satisfied. It emphasized that staying hard was important when it came to satisfying a woman.
Donnie got his chemistry set out and worked all afternoon, perfecting the implied powerful anatomical changes to his cock. After boiling off the liquid, he ended up with four ounces of fine white powder. The internet directions guaranteed that one teaspoon of the powder in a cup of liquid would deliver the pledged results. Donnie drank the concoction and set about waiting for the reaction to take place. By dinner time, nothing had changed. His cock wasn't any longer, and he didn't feel any different.
After dinner, the family settled in the den to watch TV together. Donnie was fidgety and kept leaving the room every twenty to thirty minutes to check and see if there were any changes to his cock. There wasn't. He did seem to get an erection at the slightest stimulation, but that was fairly typical for a teenage boy with raging hormones. Around ten o'clock, the family retired to their bedrooms for the night. Donnie had a restless night. He kept dreaming of naked girls parading before him. Every once in a while, his dream would include his mother and sister among the naked girls.
Donnie came down for breakfast the next morning and took a step into the kitchen. His Mom was busy preparing breakfast as usual, but something was different. Donnie shook his head and looked again. Why hadn’t he noticed the flare of his Mom’s hips before? She was wearing a dark knee-length skirt and a sheer white blouse that sort of hugged her waist. Her butt curved nicely under that skirt. The outline of her lacy white bra was unmistakable under her sheer white shirt. Was that sexy? For the first time in his life, he thought it was. He could see the swell of the right side of her boob under her shirt, jiggling as she stirred the pancake mix with a large spoon. “Holy cow," he thought to himself. He had never noticed before, but his Mom was hot. He got an erection looking at his Mom. He had to sit down and hide it from her.
A moment later, Donnie’s sister entered the kitchen and took her usual place across the table from him. Looking up from his breakfast, he stared at his big sister. How had he not noticed how pretty and delicate she was? Soft blue eyes. A warm, engaging smile. His older sister looked different. Her bra straps are visible on her narrow shoulders. And her boobs? Oh, God, her boobs are small and firm, just hanging out right there. How had he not noticed them before? The truth is he’d never noticed Lucy like this before. Her trim little hips. Her dainty nose. Her long, slender neck. How had he never seen it before? He tried to smile at her. His cock got uncomfortably hard, and he attempted to acclimate it covertly. His Mom gave him a quizzical look. Donnie tried to engage his big sister with small talk about the yearbook she was editing for her college but kept stumbling over his words. He finally gave up and excused himself and left for school.
Donnie's cock hadn't made the changes promised on the internet, so he studied the chemical formula and decided that the dosage must depend on body weight. Instead of one teaspoon of the white powder, he put a tablespoon in a cup of hot tea and drank it with his dinner. At about two o'clock in the morning, Donnie woke up. It was still dark outside. He rolled over in his tangle of sheets and groaned. Something felt odd. Very odd. He tossed and turned, trying to get comfortable. Something was wrong with his cock. Donnie rolled over, jumped out of bed, and pulled down his boxer shorts to examined himself. His cock was hard, very hard. It was not any longer, but it was swollen fat and ached terribly. It was the worst case of blue balls he had ever experienced. He urgently needed to cum. Donnie rushed to his bathroom, pushed his boxers down to his ankles, and began to masturbate aggressively. He tightened his hand around his hard cock and pounded away. Images of his Mom and sister surged into his head. He seized his cock and increased the rhythm. He was harder now than he had ever been in his life. His cock was, indeed, a sight to behold. The head was purple and mushroom-shaped. The veins were sticking out and throbbing.
An hour later, Donnie still hadn’t cum. Blood drained from his head and filled his swollen cock. He was becoming dizzy, and his arms felt like they were about to fall off. He’d never experienced anything like it. He waddled over to the bathroom window with his boxers still around his ankles and pulled the window open. The cold, crisp air cleared his head. Donnie kicked his boxers off and deposited them in the clothes hamper. Donnie shared a Jack n’ Jill bathroom with his big sister, Lucy. He opened the door that connected the two bedrooms and made his way to his sister's bed. Donnie sat on the edge of his sister's bed, crying because of his painfully hard, aching cock. He sobbed in pain as he shook her shoulder. She woke with a start and said, "What is it, Donnie? Why are you crying?"
“It’s my cock,” he blubbered. ” It hurts so bad I can’t stand it.”
Lucy sat up in her bed and saw that Donnie was nude from the waist down, and his cock was standing at attention. Lucy had never really given much consideration to her little brother’s cock other than the few times she noticed his arousal creating a bulge in his pants.
“What the hell do you want me to do, Donnie? I’m your SISTER! I’m not supposed to see your…. your….. thing …. like that.
“Please help me, Lucy,” he pleaded, “I just need to cum.”
“Well, go in the bathroom and jack-off, or spank your monkey, or whatever the hell guys do to make themselves cum,” Lucy bellowed.
"I've been beating off for over an hour and a half. I've come close, but I haven't been able to push myself over the edge and cum," Donnie explained to his sister. "I thought maybe if you did it, I would finally cum."
“Donnie! I’m your SISTER! I’m not supposed to touch my brother like that. It’s not right. It’s called incest.”
” Please! Please! Please, Lucy! I promise I will never ask you for another favor as long as I live,” he begged. “Just help me cum this one time.”
Lucy considered the agony on her little brother’s face. Her heart went out to him because she could see he was sincerely hurting. Lucy relented and asked her brother to lie on his back. She then crawled between his legs. Lucy set back on her heels and examined Donnie’s cock for a moment. She had seen a lot of cocks, but never a cock this large. Lucy dated a lot of guys in high school and college and had become very skilled at giving a handjob. It wasn't one of her favorite things, so she learned to get them off quickly.
Lucy wrapped her hand around Donnie’s cock and said, “You are going to owe me big time, Donnie.”
Lucy placed both hands around her little brother’s cock and felt the veins and muscles under his skin. Donnie's cock twitched and throbbed under his sister's skilled touch. Lucy first used the 'twist and turn' method, where she would slide both hands up and down his shaft while twisting each hand in the opposite direction. Lucy would alternately glide the palm of her hand over the head of Donnie's cock, every third or fourth trip to the top of his shaft, paying particular attention to his sensitive frenulum.
Both of those approaches usually got a guy off rather quickly. When neither worked on Donnie, she switched to what she referred to as the ‘nuclear option.' An established technique that always resulted in an explosive orgasm. That technique consisted of gently massaging Donnie’s balls with one hand while sliding her other hand up his pulsating cock to his mushroom as she again stimulated the frenulum. While continuing to work his shaft in that manner, she tickled his balls with her fingertips. No one had ever lasted more than a few seconds under that method.
As luck would have it, nothing happened. Lucy fell to her brother's side, totally exhausted. Her arms were aching, and her fingers were numb.
“Don’t stop,” Donnie shrieked, “I was almost there!”
“I’m sorry, Donnie. I’ve tried everything I know to do.”
Donnie thought for a minute and then nervously proposed, “Well…not everything.”
“What do you mean,” Lucy asked?
Donnie hesitated a long moment then gingerly said, “You haven’t tried your mouth yet.”
Lucy bolted upright in the bed and glared at her little brother. Her face was red, and she could feel the fierce heat rising from her shoulders and neck. Through clenched teeth, she growled, "You are such a fucking pervert. I am your SISTER for God’s sake! Sisters don’t give their brother blowjobs. No way am I going to let you stick that monster in my mouth!”
Donnie thought for a minute and then said, “Can I stick it in your pussy?
“Absolutely not,” she growled!
Donnie started crying again and moaned, “It hurts so bad, Lucy. I can’t stand it much longer. My balls have never felt so full and hurt so badly. I know if I can stick it in something warm and wet, it will make me cum."
Lucy had always had a tender spot in her heart when it came to her little brother. She could never sit by and let him goes through such agony and pain without at least trying to relieve his pain. Lucy leaned forward on her hands and knees, opening her mouth. In one move, she engulfed his thick cock to halfway. The heat that enveloped his groin was intoxicating. Donnie reached down and gripped the sides of her face. He watched in amazement as his sister gave him his first blowjob.
"Mmmmmmmmm" Lucy moaned as her lips glided up and down his shaft.
Donnie shuddered as Lucy swirled her tongue around his sensitive tip. He thought his balls were tight, but when her hand came up and cupped his full sack, Donnie thought he was going to blow right there.
Lucy gave a mewling sound as Donnie began to move his hips, slowly fucking his sister’s mouth. He felt his engorged head bump the back of her throat but kept pumping. He’d been dreaming of this forever, and he would not be denied.
"That's it, Sis, suck your little brother’s cock." He groaned.
"Yuullaakkkkk," Lucy tried to talk as he shoved his cock down her throat.
Donnie felt his balls slap against Lucy’s chin as he buried himself in her warm wet mouth, pushing until he felt his cock enter her throat. There was no question of who was in charge now as seven inches of his hard cock stretched Lucy’s throat with each thrust.
Donnie could hear Lucy taking breaths through her nose, looking down he watched her spit dribble from the corner of her mouth and down her cute little chin. That sight alone was almost enough to make him want to blow his load down her throat right then and there, but he didn’t want to stop feeling the magnificent pleasure of his sister’s mouth just yet.
Lucy’s eyes fluttered open, and she stared up into his face. She released her grip on Donnie's shoulders and slid her hands down his back until she gripped a cheek of his ass in each hand. She lifted his ass toward her face as she forced her mouth down onto his cock until it bumped the back of her throat.
Donnie couldn't believe the slut his sister had kept hidden inside. Every one of her calculated movements reeked of sex and lust. When Lucy released Donnie’s ass cheeks from her grip, he watched as Lucy’s mouth sucked hard around his crown, and then slowly slid down until her nose was buried in his pubic hair. Donnie could feel his cock enter his sister’s throat again. “Fuck, she had just deep throated him again,” he realized.
At the same time, Lucy reached up and pulled her nightgown off, and he could only stare at her nude body came into view. There is nothing like having a naked and horny slut kneel between your legs with your cock shoved down her throat, he thought.
Donnie couldn't stand it anymore. Reaching down, he intertwined his fingers into her blond hair, holding her head still he began to arch his hips. Donnie could hear her wet slurping as he began to fuck her hot mouth. He thought she might get mad, but instead, she only hummed her approval of him taking command. The vibration from her humming went straight to his boiling balls, sending his body into overload and shutting his brain down at the same instant.
"Take it, Sis, suck my cock," he roared as his orgasm built. "I think I am going to fucking cum," he told her!
Donnie arched his hips up harder, driving deeper. He could hear Lucy start to gag on his length, but she seemed to feed off his motion. Donnie felt his balls slapping against his sister's spit covered chin. The sight of his cock buried down her throat was too much. He was on the verge of cumming.
Her mouth suddenly slipped off his pulsating cock, and she began to shudder as her orgasm raced through her body. Donnie felt the pressure ease off his glands, making his balls start to settle back down. Lucy was still shaking and convulsing from her orgasm. Donnie clutched her to his chest and pressed his lips to her parched lips. Their tongues found each other and danced.
Lucy disengaged from their kiss and said, "Fuck me...please!" She sounded like she was begging.
That was all Donnie needed; he grasped his pulsing cock in one hand while he supported himself on the other. Aiming the engorged head to her swollen labia, he lowered his hips. Just as the tip of his cock touched her moistness, Donnie looked into her eyes. He could see the fire glowing in her eyes.
Donnie’s cock head parted Lucy’s labia like wet petals as he slid the head inside, accompanied by a soft, moist sucking sound. He could feel her tight silky walls gripping his cock as he pushed deeper.
"Oh, Jesus," Lucy groaned as she stared into his face. "Slow Donnie," she gasped. "I’ve never had anything this big in me."
Donnie’s cock is the biggest cock she has ever had in her tight pussy, he realized. No wonder her walls felt like a velvet vise, she was as tight as a virgin against his seven inches. With a grunt, he pushed down, down, down, sliding a couple more inches into her.
He watched as Lucy's eyes fluttered again, her mouth opening in a silent “Oh” as her body gave a small spasm under him. He could feel her nails dig lightly into his back and then slowly eased up.
"My God," Lucy breathed out a long sigh. "I just came again, Donnie. Fuck, that was good." A small smile crept over her face. "Fuck your big sister, good and hard little brother," she urged him.
With only half his cock inside her tight pussy, Donnie began to rock his hips, slowly sliding in and out of her now dripping pussy. With each forward motion, he slipped more and more of his length inside her.
"Oh shit," Lucy groaned as his pelvis came down on hers, his entire seven inches now buried to the hilt inside her sopping vagina. Lucy’s grip tightened on her little brother’s hips, holding him in place.
"Don't move for a second," Lucy gasped. “Let me do the work for a while.”
He could feel her hips grind in a slow circle under him as her Venus mound pressed against his pelvis. There were rhythmic like waves pulsing along her tight walls as his big sister skewered herself on his manhood.
"Oh, little brother," Lucy moaned "I want...I'm going to...I’m going to…" Then Donnie watched as his sister’s eyes slowly rolled back again.
"Ooohhhhhhhh" Lucy softly whimpered as her entire body jerked under her little brother. She stopped moving as a torrent of fluids gushed out to soak Donnie’s cock and balls, and then slowly run down the crack of Lucy’s ass to drench the sheet under her.
"Wow," Lucy whispered as her eyes refocused on Donnie’s face. "Are you sure you were a virgin, little brother?" she asked.
"I was until a moment ago," he smiled back. "Why?"
"Because you have already made me cum three times," she told him. "Yet, you haven't even started to really fuck me."
Donnie pulled slowly back until just the head of his cock rested inside her wet opening. Hovering over her, Donnie locked eyes with his sister. Donnie gave a silent thanks to hours of watching porn that had prepared him to know what to do to please his beautiful sister sexually.
"Oh, so now you want me to fuck you,” he grunted? “You mean like this!"
Donnie then rammed his cock down hard, slicing down through her velvet walls, driving deep, deep, deep. Lucy’s legs shot out and then wrapped around her brother’s waist as she scrapped her nails painfully down his back. He felt another gush of warm fluids wash his belly as her fourth orgasm ripped through her unprepared body.
"Oh my, God! YESSSS," Lucy screamed as she convulsed under him again.
Donnie’s hips rose and fell as he pounded down into her with unrestraint. One advantage to her brother was an almost unlimited energy supply supplemented by the chemical concoction that kept his dick unusually hard. Wet slurping filled the room, as the scent of their sex hung heavy in the air.
"Fuck me...fuck me..." Lucy chanted as her little brother, hammered into her. "Own me, little brother," she said. "I'm yours for the taking."
Donnie knew he wouldn't last much longer. It would be a welcomed relief to his aching balls, but he didn't want the pleasure of his cock sliding in and out of his sister to ever end. Donnie could hear his balls slapping his sister’s cum soaked ass as he fucked into her with everything he had.
Donnie watched as Lucy devolved into a quivering mass under him. Her body was continuously jerking and spasming. Her hands slid up his back to the sides of his face.
"My little brother is making me cum so fucking hard," Lucy's seriously lust-filled voice washed over Donnie’s face.
Donnie felt Lucy’s walls rippling along his shaft, trying to milk the boiling cum from his balls. As he watched his big sister orgasm a fifth time, his body gave in to the sensations as his balls started to tighten. Lucy gasped, her eyes locking to his. Donnie tried to keep looking into her eyes as his orgasm hit, honestly, but it wasn't going to happen. Donnie’s eyes rolled back in his head as his released cum exploded from his balls and shot the length of his cock.
"Oooohhh," Lucy gave a primal roar as the first blast jetted out to wash her spasming walls.
Donnie refocused on Lucy’s face as best he could as his ass cheeks tightened, and a second burst pumped out to flood her waiting pussy. He could see the look of wonder in her eyes.
"Jesus," Lucy moaned. "I can feel it, oh my God." She shuddered under him.
By the time the last spasm of his cock hit, it had to be three or four hot ropes he had let loose inside her. Donnie rocked back on his heels between Lucy’s lewdly spread thighs, looking down between their joined bodies.
The erotic sight of his cock sliding from her tight pussy was exciting enough. Still, the additional image of white globs of cream that matted both their pubic hairs, as their mixed cream seeped from her sent a shiver down his spine.
"I'm no longer a virgin." Donnie crowed as he looked down at his beautiful sister.
"No, you're not" Lucy reached up and ran her fingers down his hairy chest. "Now, my BIG little brother is a man." She said.
As Donnie slid his cock free of Lucy’s clutching pussy, he was thrilled to see it coated with their slick goo, and his balls no longer ached and throbbed. He was even more excited to realize that after emptying his balls, he was still rock hard. He wanted more of his sister, and he intended to have her.
"Am I your man?" Donnie asked as his sister stared riveted at his throbbing cock.
"Forever little brother," Lucy whispered back.
Donnie reached down and began to roll Lucy onto her stomach. Pulling up on her hips, she rose to her hands and knees on the bed. She looked over her shoulder at him as he positioned himself behind her. There was a fire in her eyes he had never seen before.
"Are you going to mount me?" Lucy growled. "Are you going to Fuck your big sister like a bitch in heat?"
Donnie snarled with lust as he dragged the swollen head of his cock along with his sister's cum soaked lips. He never had in his life heard his sister talk like that; it was as if she had become the slut he’d dreamed about.
"I fucking love this position," Lucy moaned. "It's been too long since I was so satisfied; now fuck me like the whore I am. Every hole I have belongs to you now, little brother."
Donnie slammed into her soaked pussy and asked, “Lucy, I know I promised you I would never ask for a favor like this again, but do you suppose you could arrange for me to fuck some of your sorority sisters the next time I get hard like this?”
“Donnie! I’m your SISTER! I get first dibbed on your wonderful cock!”