Cum Research with Sister

Ella was in a state of panic after she entered the lab that morning. She distinctly remembered putting the sperm sample in the cooler the day before. Instead it had been sitting on the counter all night, at room temperature, ruined. At this point, she could either take the blame for the testing delay, or she could find another cum sample as quickly as possible.

After freaking out for a moment, she managed to compose herself.

Ella's mother, a lead researcher, had pulled some strings to get her this position. Her older brother worked there also. Failure would bring shame to the family! She needed fresh semen, and fast. But how? She quickly considered all possibilities and nothing seemed viable in such a short amount of time.

There was another option, however. A plan so shocking, she was amazed the idea had even crossed her mind. Though crazy, it was plausible and would solve her problem. No one in the lab would ever know of her screw-up.

Could she really pull it off? After thinking for a few more seconds, she found her resolve. It was necessary, and in the name of science, she would make it happen.

Ella put on her lab coat and placed a small beaker in her pocket. Walking casually through the facility felt surreal as she contemplated her immediate future. Would the next half hour haunt her for the rest of her life?

Her brother Jeff was trustworthy. Over the years, they had watched each other's back countless times. He was the perfect older brother: smart, patient and protective.

Most importantly, Jeff was a HUGE cummer. She discovered this having accidentally barged in on him a few times. Her brother could cum in spades. Not only was it high in volume, his cum was also high in quality. She could tell if he had recently masturbated by simply walking by his bedroom door and taking a whiff; the aroma was unmistakable. He was both potent and virile.

At this moment, Ella desperately needed his special skill and wondered if he would come through for her.

Ella also thought of her Mother's advice; 'If you ever need anything, just ask your brother. I've instructed him to help you whenever possible.'

This may not have been what Mom had in mind, but it would surely be enough for the much needed sample.

She arrived at his lab on the other side of the building. After making eye contact with Jeff, she silently summoned him by nodding her head towards the office in the corner of the large, sterile looking room. It wasn't completely private, but it was secluded enough for her top secret plan.

Once the office door was closed, she went straight to business.

"Jeffrey, I need to talk to you," she said, using his full name to convey the seriousness of the situation.

"What's going on?" he asked.

"Oh my god, I'm freaking out right now! I accidentally ruined the sperm sample we need for today's test!"

"Yikes. Well, it's not the end of the world. These things happen. People don't get fired for little slip-ups, if that's worrying you."

"I'm not worried about being fired," she said nervously. "I'm worried about our reputations since Mom got me this job."

Jeff thought for a moment. "Ok, relax. We need solutions. Any ideas?"

"Actually, yeah. I want to replace the sperm sample. But we need a healthy size sample to cover all the testing scheduled for today."

"How are you going to do that on short notice? Did you reach any of the regular donors?"

"Too much hassle," she said nervously. "If I contact them, then everyone will know of the mistake."

"Then who will produce the sample?"

Ella cleared her throat. "I was hoping- you."

"Me?" he asked, taken completely aback.

"Jeffrey, I've seen your loads before. They're huge! If you give me a big enough sample, all of my problems will disappear. It'll be our secret and I'll owe you big time."

"How much do you need?" he asked, while pushing away the embarrassment in order to help his little sister.

Ella removed the small beaker from her pocket.

"This much," she said, pointing to the exact measurement scale.

He shook his head. "Guys can't just shoot massive loads at the drop of a hat. It's a bit more complicated than that."

"I know. I know. You need the right stimulation, both physically and mentally."

"Then you can see why it's a problem for me to fill that up on demand."

Ella took a deep breath. "Which is why I'm prepared to help you."

"How?" he questioned.

"I'll do whatever you need," she said suggestively. "You know what I'm talking about, so please don't make me say it. This is humiliating enough."

"Jesus," he sighed.

"You know I'm only asking because it's an extreme emergency."

"Honestly, it would better to just admit..."

She put a finger on her brother's lips. "Hush. Do you want me to suck your dick, or not?"

Her coarse words seemed to do the trick because Jeff's eyes lit up with excitement. Ella could see that her brother was now very interested (and possibly already erect). She moved her finger away so that he could speak.

"Are you sure?" he confirmed. "Right here? Right now?"

She nodded. "I'll suck your dick, but Mom can never know."

"This might be the best way."

"I'm glad we're on the same page. You're a lifesaver."

"Yes, but I can only do it on one condition," Jeff spoke haltingly.

"What? Getting a blowjob isn't enough?"

"No! I mean... yes! I'm very grateful. But... if you want a large quantity, there's something else I need."

She crossed her arms. "Just spit it out already- no pun intended."

He took a deep breath. "Do you mind if I talk dirty while it happens?"

"Talk dirty... as in..."

"Dirty sex talk," he confirmed. "While you perform fellatio on me."

She sighed, "Does it get you off in a big way?"

"Look, dirty talk is something that really intensifies my orgasms and makes me cum like a volcano."

"Then go right ahead."

"But the thing is - and this is really embarrassing - I love family play. If you want a big cum dump, this is the best way to get it."

Ella's eyebrows arched. "What the heck? Are you some sort of pervert or something?"

"No! It's just fantasy stuff. Do you think this is easy for me? I'm doing this as a favor... for you."

It was a good point; Ella was in a serious bind. Without those cum samples, her reputation in the lab would be tarnished. Worse, her Mother's reputation would be damaged, too. They were supposed to be a smart family!

"Go ahead," she said. "Whatever helps."

He nodded. "Okay, so, this is awkward."

Ella stood there like a mannequin, staring her brother straight in the eyes.

"This is a lot harder than I thought," she said.

"What time do you need it? I could always warm myself up with porn. It'll take longer, but provide a large volume."

She sighed, "I need it in about 20 minutes. I know, I'm a screw-up. But I am trying my best and sometimes it gets overwhelming."

"This is a demanding job, Ell. As far as I'm concerned, you're showing a lot of initiative by trying to fix this problem."

She smiled, "Thanks, that makes me feel better. I am showing strong initiative, aren't I?"

"You're seriously unstoppable. I love that about you."

Ella summoned her courage while taking a deep breath. She sank to her knees, placing her face just inches away from her brother's crotch.

"How's this for initiative?" she asked, looking upward at her brother.

"Can you do the rest? I'm too nervous to expose myself."

"Well, this is my fault, so let me take control."

Ella unzipped and yanked down her brother's pants, exposing his equipment. As expected, he was already erect, but his cock seemed to swell even more the moment it was exposed. This was her first time seeing it up close and she could tell why Jeff was such a huge cummer. He had a rock solid 'foundation' for cum production. His balls were like a male porn star's!

Taking yet another deep breath, she kissed the tip of the penis, making Jeff squirm.

"It's okay," she whispered, holding the shaft. "Just hold still."

She nibbled on the head and started to suck. Shockingly, it grew even bigger from her oral stimulation.

"That's right, my little cocksucking sister," he moaned. "Keep going, your mouth is so warm and wet."

Ella tried to ignore his words as she kept giving head. Hearing his moans raised her hopes that she could help him release a massive load. Knowing it would solve all her problems motivated her to unleash more oral tricks.

Jeff moaned again, "That's right little sister, suck your big brother's cock. I've thought about pushing my dick into your sweet mouth for a long time."

She spit the cock out and glared at Jeff. "What the hell?!"

"Oh, sorry. Was that too far?"

Ella was still shocked. "I don't know. It's just... you've really wanted... this... from me?"

"No!" Jeff turned beet red, but his cock remained rock hard.

"Wait, you don't want me to suck your cock?" Ella was confused.

"It's just part of the dirty talk. I swear, it'll be worth it because I feel a big load building."

"Hmmm. It's kind of unusual."

"Too much Literotica, perhaps," he confessed. "You can blame HeyAll and SueDanym for that."

"Well, I've never heard of those perverts, so I'm blaming you."

Jeff suddenly became defensive, pulling his dick out of Ella's hands.

"Do you want my help or not?" he asked, giving a firm ultimatum.

It was a pivotal moment in their brother/sister relationship, and Ella made a snap decision that she would fully accept her brother and his kink. Her budding career was on the line!

She grabbed his dick back. "Whatever it takes, I'll go along with it. I'm desperate and will do anything to make you cum hard, big brother."

When she winked, Jeff smiled and sighed. As he visibly relaxed, she knew this was the key to a massive load of fresh, hot cum.

"Good job, little sister," he said, while patting her head. "My load is building."

"That's the spirit. Now let your cocksucking sister take care of you."

Doing her best to make this as nasty and incestuous as possible, Ella sucked while looking Jeff straight in the eyes. Typically, she only made eye contact for a few moments while giving head, because it embarrassed her. But somehow, she found it reassuring to look into the face of someone she truly loved, while slowly devouring his cock.

Every so often she'd take her mouth away and stroke his dick, while being sure to compliment him in the most sisterly way. Surprisingly, it felt very natural for her to feed his secret desire. She proudly confessed, both to him and herself, that the strong smell of his cum usually made her horny. And that his dick was bigger than any of the other guys she had sucked in the past. Maybe his Literotica preferences weren't really so bad.

She knew she was making headway while whispering, "God, I love the fact that I'm sucking off my own big brother's enormous cock. I am such a naughty little sister."

After putting the dick back inside her mouth, she knew Jeff was close to producing a tremendous load of cum. This was wildly exciting for Ella; her heart pounded like she had just sprinted up a hill. How could this be? Sucking other guys never made her feel this way. Wait! Her pussy was wet, too! She suddenly realized her panties were saturated. Apparently, Jeff wasn't the only sibling getting off on this very taboo act.

While focusing on her brother's impending orgasm, she vaguely heard footsteps coming down the hall. Then two swift knocks at the door were heard by both siblings.

"Ell, are you in there?" Mom called from the hallway.

Ella spit the dick out and stared wide-eyed at her brother. She was barely able to tuck his hugely erect, saliva-covered dick back inside his pants. Carefully, she zipped him up.

"Oh shit," she whispered. "Act natural."

"I am," he murmured, as he hopped up and down to readjust his uncomfortably stiff dick.

"I'll do the talking."

Ella got up, wiped the saliva from her lips, and opened the door. There stood her very proper Mother, in a lab coat, wearing her thick-framed glasses.

"What are you two doing in here?" Mom questioned, eyeing both of her children.

"Well, your birthday is coming up, and we needed privacy to discuss your gifts."

Mom smiled, "That's actually very sweet. I don't recall you two ever working together on presents."

"It's my way of thanking you for this job."

"Speaking of which, do you know what happened to the sperm samples? The vials look like they've been washed."

Ella gulped. "Oh, the samples? I had to move them because of a small technical error. Don't worry, they are being safely stored."

"Great. Where are they? I want to get an early start."

Ella's heart skipped. "I'll bring them up in 10 minutes, okay?"

Mom tensed and Ella wondered if she had smelled Jeff's pre-cum somehow. While eying both her adult children, Mom's eyes narrowed and her face turned slightly.

Apparently, having figured out the current dynamic, Mom looked disappointed. However, after a moment, a begrudging look of admiration appeared. It seemed she was proud of her daughter for going the extra mile.

"10 minutes, tops," Mom said, shaking her head.

"Thanks, and sorry, Mom."

"Sorry? For what, exactly?"

Ella pursed her lips and tilted her head. "I'll come to our lab in 10 minutes. This shouldn't take long."

Mom could barely make eye contact with her children as she lowered her head and left.

Ella felt deflated for a few seconds as her self-esteem collapsed. But she had a responsibility to the department and centered herself once again. Closing the door, she locked it and marched over to her brother.

"Oh god," Jeff said in defeat. "Mom figured it out."

Ella sank her to knees. "I know. I'll need to have a long talk with her to explain everything. In the meantime, let's get back to business, or pleasure, as the case may be."

She undid her brother's pants and freed his straining cock, which seemed even harder than before. How was this possible?!

"Oops," his cheeks burned.

She looked up at him. "Holy shit! Getting caught by Mom really excited you, didn't it?"

"I don't know," he said, confused by the reaction of his body. "Trust me, I'm as mortified as you are. I don't know why this is happening."

She stroked his shaft and grinned. "So, my brother likes being caught."

"I... I don't know what to say."

Ella sucked his massive balls and licked his shaft. "You know, when Mom realized what we were doing, I could tell she was disappointed that I was sucking your dick at work. Can you imagine? Mom got both of us these great jobs, and here I am, giving you sexual pleasure in an office."

"Oh fuck."

"You know, Mom and I are both ambitious women," Ella said between deep long passes, as his cock went even further down her throat. "Oh yeah, Mom understood why I'm doing this. She knew I screwed up the cum samples and why I had to refill them- with your cum!"

"Oh Jesus."

Ella sucked and stroked. She knew those taboo words were driving her perverted brother over the edge. But even crazier, she loved speaking to him this way. And she loved sucking his dick to the point of orgasm.

It made her feel powerful.

"You know what?" she asked, stroking his shaft quickly. "I think Mom might have smelled your pre-cum on my breath. I bet that's how she knew. We were very close while talking, almost face to face. I know Mom has sucked her fair share of cocks over the course of her life. She must have smelled it coming from my mouth. I wonder if she's jealous? Do you think Mom liked the smell? Do think Mom wants to join in on our incestuous fun? I want her to. Because I saw the lust in Mom's eyes when she realized your pre-cum was in my mouth."

"Really?" he breathed deeply and grabbed the sides of Ella's head.

She stroked him faster. "Yes, really. It must run in our genes. The women in our family give really, really good blowjobs. Can't you tell? In fact, who do you think taught me?"

"Mom?" he asked, as his pupils dilated.

"Oh yeah, when I turned 18, Mom spent weeks teaching me how to suck dick. We practiced a lot on her dildos when you weren't home."

"Oh god!! I'm going to burst!!"

Ella pulled the beaker out of her pocket and placed it on the table. She stood up, pulled her brother's hard cock towards the opening, and stroked him like crazy.

"Fuck!" he cried as his dick was being yanked.

Her hands worked even faster. "In here! Don't miss a drop."

Moving her hands in circular, but opposite directions as they traversed the length of his cock, Ella gave her brother a wonderful handjob. Both of her thumbs stimulated the smooth tip of his penis, through which pre-cum continued to leak. Along with making Jeff cum, she also had to make sure his aim was 100% accurate. While giving her all, she kept her brother's cock pointed towards the small, clear, glass container.

Suddenly, Jeff jerked and cried out as his eruption began. In an inspiring show of testosterone, copious amounts of his potent semen spurted into the beaker. It splashed against the sides as it flowed out of his cock and she was mesmerized. Never before had she seen such a manly production. Looking back at his contorted face, she realized giving him such ecstasy was the ultimate turn-on for her.

"Oh fuck, I need a seat," Jeff sighed, almost collapsing.

She helped her brother sit down on a chair. He very nearly fainted as his cock turned flaccid. Unbelievably, cum continued to dribble from the tip. Too tempted to refrain, she used her fingers to catch the cum and wiped it on the edge of the beaker.

"You're the best," she said, licking her finger.

He managed a smile, "Did you just eat my cum?"

"It was a little taste test. Everyone knows that cum eating goes along with any decent blowjob. Hey, don't blame me, I learned that from Mom."

His gaze sharpened. "Really?"

"Maybe, maybe not," she replied, fluttering her eyelashes. "We can talk more about it later if you want. Until then, I have to get this to the lab. Let's get you cleaned up. And thanks again. You're the best big brother in the world."

Bending over, she licked her brother clean, swirling her tongue and sucking with her mouth to clean his dick, then she helped him pull up his pants. With the beaker carefully placed upright in her coat pocket, they left the room together.

To their horror, Mom was just down the hall, talking to a colleague. Mom caught them leaving together and noticed Jeff looking completely exhausted.

The guilty siblings froze, but in the end, Mom smiled and returned to her conversation with the colleague. Was it Mom who 'accidentally' ruined the original sperm sample in the first place? After all, Mom had often encouraged the use of unorthodox problem solving techniques.

Ella was stunned by the epiphany, but in the end, she wasn't entirely shocked by it either. Mom always wanted the siblings to work closely together, although this may not have been what Mom had in mind.

The End

Contributions by the great SueDanym!

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