Madison silently cursed herself for deciding to live at home during her freshman year of college instead of the university dorms. When Madison made the decision it was because she didn't want to risk getting stuck with a roommate she didn't get along with, and to save some money; but when she heard her step-brother through the thin walls of her bedroom she regretted the decision. She had been lying in her bed trying to study when the rhythmic sounds of his masturbation started. She tried to convince herself that it wasn't that big of a deal; Nathan was eighteen years old, a high school senior, and all boys his age spent half their days beating off. But when Madison started hearing his aroused moans seep through the wall she got fed up. How was she supposed to get any studying done while listening to her brother grunting like some horny monkey?
Exhaling an irritated breath Madison crawled off her bed and moved for the hallway. Nathan's bedroom door was right next to hers, on the second floor of their parent's split-level suburban home, and she intended to let him know that she could hear everything he was doing. She assumed he locked the door, only meaning to rattle and startle him when she grabbed his bedroom's doorknob, "Nathan! I'm sick of listening to you-"
But when Madison's hand grasped the knob it surprisingly turned and the door opened inwards.
"Madison?!" Nathan yelped, "What are you doing!? Get out of here!"
Madison felt as startled as Nathan looked. She truly didn't mean to invade his privacy in such a manner and had stumbled forward into his room when the door opened. She was treated to the sight of her naked step-brother seated in his swiveling desk chair, erection in hand. Nathan was a tall boy, north of six feet, with short dark hair and his father's bright blue eyes. He had a slender frame with narrow hips; but his arms, legs, and chest carried the compact muscles of youthful athleticism. He was also very tan, Madison noticed, which looked really good on his smooth and hairless body.
Madison started to apologize, "Oh god, Nathan, I'm so sorry! I didn't mean to-"
"Get out!" Nathan screamed.
Madison was initially willing to comply and started backing out of the doorway, but she paused when she saw what was on Nathan's laptop computer screen. He had been masturbating to a picture of her lying on her back by their parent's pool wearing a skimpy bikini.
By the angle of the shot Madison guessed Nathan used a digital camera from his bedroom window, "You perv!" she quickly accused.
Nathan saw what Madison was looking at and reached out to snap his laptop screen shut.
But his action came too late. "You're in here jerking off to pictures of me?!" Madison exclaimed. "You're unbelievable, Nathan!"
"I told you to get out!" Nathan yelled as he reached for a towel and covered his mid-section. "Get out of my room!"
"Wait until your dad finds out about this!" Madison warned as she left the room and pulled Nathan's door shut with a slam.
A second slam echoed through the upstairs hallway as Madison returned to her room and locked her door, fuming over what she had witnessed. She flopped back onto her bed and considered how lucky Nathan was that their parents had gone out for dinner. She didn't really intend on telling them about Nathan masturbating, she only said that to scare him, but if they would've heard what just happened Nathan would have had some explaining to do.
Picking her textbook up Madison attempted to study once more, but as she began reading she thought of Nathan naked in his chair with his erect cock in his hand. Madison couldn't help wonder how big it was, as she hadn't gotten a very good look at it. She guessed it was sizable though, by how much was sticking up from his pumping fist. She had always thought Nathan was attractive, ever since her mom married his dad when Madison was sixteen. There was no denying it; many of Madison's friends often told her how hot they thought her step-brother was.
Even though he was her brother and she had never considered him in a sexual light due to the obvious taboos of such a situation, Madison started to feel strangely aroused. He had obviously been fantasizing about her while masturbating, but why would that suddenly excite her? She imagined Nathan having an orgasm while looking at her photo, picturing him in her mind as his semen shot out and decorated his tanned and smooth torso. That fantasy created a twinge between her legs.
"Get a grip," Madison muttered to herself. She closed her textbook, unable to focus on it, and tried not to think of her step-brother. She had a boyfriend, after all
Madison was pulled from her musings when a knock came on her bedroom door. "Go away," she growled.
"I need to talk to you," Nathan's muffled voice came from the other side.
Madison sighed and moved to sit at the edge of her bed, "You're not naked, are you?"
"Of course not," Nathan called. "Please let me in?"
"Do you have your camera?" Madison asked, unable to keep herself from teasing him a little.
"Come on! Please, Maddy...?"
Madison got up, "All right, all right." When she unlocked her door and let Nathan in he was dressed in a pair of sweats and a tee shirt; she almost felt let down that he wasn't still naked.
"You're not really going to tell my dad about this," Nathan walked into Madison's bedroom, "are you?"
"Of course not," Madison replied, returning to the edge of her bed. She and Nathan may have not always gotten along, but after their parents were married the two had adopted an 'us vs. them' policy and generally kept one another's secrets.
"But you kind of freaked me out," Madison added.
"I'm sorry," Nathan sounded sincere as he sat in Madison's desk chair.
"For what, taking pictures of me in my bikini or for jerking off while looking at them?"
Nathan dropped his forehead to a palm, "Both, I guess."
"Can't we just forget it happened?" Nathan pleaded.
"Yeah right," Madison scoffed. "Like I can just strike it out of my memory. How many pictures of me do you have, by the way?"
Nathan looked slightly sheepish, "Not that many."
Madison's eyes narrowed, "You don't have any of me naked, do you?"
"Of course not," Nathan sighed, less than thrilled at being interrogated by his sister. "God, I can't believe you caught me masturbating, this is so humiliating."
"Whatever, that part doesn't bother me at all. I mean, you're a guy, all guys jerk off. I'd be more worried if you didn't." Madison felt a little sorry for Nathan, hoping to make him feel less embarrassed, "I masturbate too, you know."
Nathan glanced up, surprised by her admission.
Madison noted, "I'm a little more subtle about it..."
Nathan grinned at that, despite the humbling situation he found himself in.
"But why were you looking at pictures of me?" Madison wondered. "Can't you find any pictures of naked girls online to look at, like a normal guy?"
"Yeah, I look at those too-"
Madison lifted her palm, warning Nathan that he was about to give her too much information.
Nathan sighed, still embarrassed, and decided honesty might be his best path. "You're hot, all right?" he blurted out. "Like, seriously hot."
Madison blinked. Nathan's honesty didn't surprise her nearly as much as the fact that she felt so flattered by his words.
"You're a legend at high school," Nathan continued. "All the guys still talk about you, even though you graduated last year."
Madison rolled her eyes and could only imagine the locker room talk, "So you want to have sex with your step-sister, is that it?"
"No, of course not," Nathan scowled. "But you're really sexy, you know? It's just fantasy. A private fantasy you were never supposed to know about."
Madison gave Nathan a sympathetic look. She understood completely what he meant. A person shouldn't be persecuted for their private thoughts in the throes of masturbation; she herself had more than her share of kinky fantasies while indulging in self-pleasure.
"How often do you do it?" Madison asked.
Nathan gave her a quizzical look.
"Jerk off," Madison clarified. "How often do you jerk off?"
"Jeez, Maddy..." Nathan looked embarrassed.
"I'm not going to tell anyone or anything," Madison promised. "I'm just curious."
Nathan lifted a shy shoulder, "Every couple days, sometimes every day."
"How often do you fantasize about me when you do it?"
Nathan looked down to the carpeted floor, reluctant to answer.
"Come on, Nathan," Madison urged. "Just tell me, I promise I won't get mad."
Nathan's voice was barely a murmur, "Lately? Every time."
There was that twinge between her legs, again. Madison could feel it like a tuning fork echoing the sounds of her libido. Why was she so aroused by the idea of Nathan masturbating to her? Was it because he was so attractive? Was it because the idea was so taboo?
Madison inquired, "How many times have you done it today?"
"That was the first time," Nathan replied, still shy towards his step-sister's line of questions.
"You didn't get to finish, did you?"
Nathan gave her an irritated look, "Obviously not."
"Do you want to?" Madison asked in a soft voice.
Nathan misunderstood, rising from the chair, "Stop teasing me, okay? It's embarrassing enough. I'll delete your pictures from my hard drive and-"
"I'm not teasing you," Madison said.
Nathan squinted at her, confused.
Her chest was pounding and Madison could barely believe what she was about to do, but a thrill was buzzing inside her that she had never felt before. Folding her arms, she grabbed the hem of her top and pulled it off over her head.
Nathan hadn't expected that. He stood motionless as Madison cast her shirt to the floor, though she still wore a pair of cozy pink track pants. Her perfectly-sized breasts were contained in a white lacy bra, and the skin over her torso was a golden tan from hours spent in the backyard sunning herself. Madison had the tiniest hint of baby fat at her tummy, which wrinkled in the cutest way due to the way she was sitting on her bed.
"I'm not teasing you," Madison repeated, tossing a hand through her long blonde hair. She thought briefly about her boyfriend but quickly pushed him out of her mind, overcome with Nathan's flattery. "I want you to know that I'm cool with it. Do you want to finish right now?"
Nathan lifted his eyebrows, "You mean right here?"
Madison nodded as she started slipping the track pants down her legs, taking her socks off with them.
Nathan swallowed when he saw Madison's lacy white panties stretched between her slender hips. Her bare legs looked just as fantastic as her torso, tanned and toned to perfection.
"Do I look sexy?" Madison asked.
Nathan nodded stupidly.
"Well don't just stand there," Madison instructed. "Show me."
In a daze of surprise, confusion, and lust, Nathan pushed the hem of his sweatpants down over his thighs. His penis was already hardening at a visible rate, rising from its flaccid state to stand straight up in attention. Madison guessed the thing to be seven and a half, maybe eight inches long when erect. He was circumcised, and Nathan kept his bush of pubic hair neatly trimmed. She thought his cock looked beautiful.
"Do you use lubrication?"
"Hand lotion," Nathan replied quietly.
Madison reached to her bedside nightstand and grabbed a small tube of moisturizer, tossing it to her step-brother. She watched as he squeezed a puddle of it into the center of his palm, "You have a really nice cock."
"Thanks," was all Nathan could think of to say.
"Are you a virgin?"
Nathan shook his head.
Madison smiled, "Who...?"
"Millie," Nathan answered.
"Your ex? I thought she wanted to wait for marriage?"
"That's why we broke up," Nathan explained. "She felt guilty after we did it and blamed me for pressuring her."
"So only once?" Madison asked.
Nathan nodded, reaching down to his erection.
"No other girls?"
Nathan shook his head, grasping his cock.
Madison grew quiet for a moment, mesmerized by the sight of Nathan starting a slow stroking motion. He spread the moisturizer over the entire length of his shaft, until it was good and slick, and then he grabbed it tightly and began slowly pumping his fist up and down.
"What do you think about," Madison whispered, "when you're looking at my pictures?"
Nathan didn't answer her, though he was starting to breathe heavy.
Madison rose from the bed. "It's okay," she assured him. "Is the picture of me in my bikini your favorite?"
"Yeah," Nathan whispered. "Your skin looks so hot in the sun, and you're kind of sweaty. I think about kissing your body; licking my tongue along your thighs."
Madison shivered at the thought. Feeling courageous and aroused, she turned around and took the hem of her panties, pulling them down off her bottom. She stuck her ass towards Nathan and pushed the crack of her butt against his cock. He let go of himself as Madison wiggled her butt against his erection, "Do you think about cumming on me?"
"Yeah," Nathan admitted, growing bold from Madison's actions. He stared down at the small of her back as she rubbed against him. "I usually imagine cumming on your stomach."
Madison rolled her hips, letting Nathan's cock slide against the crack of her ass. Looking over her shoulder, she grew even more excited by the lust-filled expression on her brother's face. "Why my stomach?" she wanted to know.
"Because you have a really sexy tummy."
Madison turned and moved closer, within a whisper of her step-brother, taking his hand. She placed his palm against the mostly-flat contours of her stomach, encouraging him to touch her. His touch felt curious and electric as his hand smoothed over her skin.
"You're so fucking hot, Maddy," Nathan moaned, once more jerking himself off with a swift pace.
Madison placed her hands on Nathan's chest, turned-on by the lurid sounds of her step-brother's lubricated shaft. "You can cum on me if you want to," she whispered, letting him know it was okay, "you can cum on my tummy."
Nathan shuddered and grabbed the side of his sister's torso, squeezing the soft fleshy spot right above her hip. His secret fantasy had suddenly come true and it was more than young Nathan's sensibilities could bear. He wanted the moment to last longer, but his orgasm erupted beyond his control. A stream of milky fluid flew up between the siblings.
Madison gasped, taking a half step back as Nathan started grunting in orgasm. She watched as his cock exploded between them, and then felt every warm spurt afterwards as Nathan took aim at her stomach. It landed upon her in the form of long ropes that stretched from her sternum to the hem of her panties.
Nothing could have prepared Madison for the fire that burned between her legs when she felt Nathan's seed against her skin. She wanted to push a hand down the front of her panties right then and there and start masturbating. Or, even worse, she wanted to get fucked. The image of Nathan mounting her filled Madison's mind, but such a taboo thing brought mixed emotions.
"That felt so good," Nathan gasped, squeezing the last bit of semen out the tip of his cock. "Maddy... that was so awesome."
Madison looked down at herself, at the dollops of cum sliding down the skin of her stomach. She heard the gratitude in Nathan's voice and suddenly worried over the reality of the situation, "What have we done?"
"This was wrong, Nathan. We shouldn't have done this."
"What do you mean?" Nathan asked, his expression twisting at the sudden turn of Madison's demeanor.
Wiping at her stomach, Madison felt the warm cum stretch between her fingers. Her head spun with a confusing mixture of desire and fear, "It's my fault. I shouldn't... I shouldn't have led you on. Nathan, I'm sorry, you should go. We need to try and forget this whole night happened."
"Did I do something wrong?"
Madison shook her head, "You didn't do anything, but we shouldn't... we should keep this a secret, okay?"
Nathan nodded, wondering what caused the shift in his sister.
"We both need to promise," Madison urged. "Okay? We won't tell anyone."
"Yeah, I won't tell anyone," Nathan promised.
"Okay," Madison nodded. "Okay. I won't tell anyone either."
"She watched me jerk off," Nathan told his friend the next afternoon.
"What?" Warren didn't believe it. "You're fucking with me."
The two boys stood on the sidelines before football practice, on the school's grassy football field, holding their helmets and waiting for the coach. They were supposed to be stretching, but neither of them was thinking about football after Nathan made his admission. Nathan had been fixated over his encounter with Madison all day and had been dying to tell someone.
"I'm telling you she was into it," Nathan professed. "She let me... you know... finish all over her stomach."
"No fucking way," Warren whispered. Their teammates were loitering all over and both boys spoke in hushed tones so as not to be overheard. "There's no way your hot-ass sister stripped to her underwear and asked you to jerk off for her. Shit like that only happens in pornos, man."
"It's the truth!" Nathan hissed. "But she got all weird about it afterwards, like she felt guilty."
"Of course she got weird about it," Warren surmised, believing the truth in Nathan's tone. "She's a chick. Sex is like chocolate to them, they want it right up until the point they remember it'll make them fat. Plus, she's your sister; that's just wrong, man."
"Step-sister," Nathan reminded him. "And we didn't have sex; she's not going to get pregnant."
"Whatever. I'm pretty sure what you did is illegal in at least three states."
"It is not," Nathan snorted. "Unless they're outlawing masturbation now."
"I hope not," Warren joked. "They'd have to lock me up for life."
Nathan smirked, "Listen, keep this to yourself, all right? The last thing I need is the whole school knowing I hooked up with my sister."
"Step-sister," Warren reminded. "And quit looking so smug, you didn't 'hook up', you only jerked off onto her, remember?"
Nathan slipped his helmet on as he heard one of the coaches blow a whistle, "Whatever. Just keep it a secret, okay?"
Madison could hear her Statistics teacher droning on at the front of the classroom, but she wasn't listening. She wondered why she even bothered attending, as she wasn't able to pay attention in her previous class either. The only thing she was able to think about was Nathan, and what had happened the previous night. Madison felt terribly conflicted, like her insides were split in half and she was a mixture of two different people.
One part of her had been thrilled like never before. Nathan was a gorgeous guy and exactly her type; she liked the smart athletic types and Nathan had always been blessed with brains as well as athleticism. Watching him masturbate and feeling the results land on her tummy had been extremely arousing. That arousal was amplified by the fact that he was so sweetly and obviously attracted to her. It was like every drop of his warm orgasm was fueled by his desire for her, which was flattering and exciting.
The other part of her worried over all the mistakes she had made. Not only was Nathan her step-brother, but they were living under their parent's roof. Madison could only imagine the expression of horror on her mother's face if she ever found out what happened. But that obvious taboo aside, Madison had a boyfriend she had been seeing for about three months and she felt horribly guilty about cheating on him. While technically she and Nathan didn't have intercourse, or anything close to it, Madison was sure Grant (her boyfriend) wouldn't appreciate her rubbing her ass all over another guy's erect cock.
When class finally came to an end, Madison hastily gathered her things. She decided she should talk with Nathan and make sure nothing like the previous night ever happened again. Nathan got to have his fun and live out his private fantasy, but that was as far as Madison could let it go. Any further sexual or romantic activity between them would be futile and only end in disaster. She could only hope that she hadn't already led Nathan on too far and that he would understand.