Emily’s Egg meets Eric’s Sperm

***

The Egg had been formed decades ago. It had sat patiently inside the ovary of the girl for twenty years waiting to make the marathon journey down a fallopian tube. Specifically that of the girl the Egg came from, Emily Cann. The previous egg had passed without her conceiving; this Egg was next. As the Egg entered the girl's fallopian tube, it began massive hormone changes inside Emily to increase her libido and lubrication, as well as help guide a sperm to the incoming Egg.

***

A WEEK LATER

Emily Cann arrived home from tennis practice, sweaty and tired. Hours outside had left her normally light skin with a slight rosy hue. "I hope that tans later", Emily thought as she caught her reflection in the hallway mirror of her parents home. Her normally dark red hair now a rosy strawberry blonde, having been bleached instead of darkened by the summer sun.

She was a beauty by any standard. All the boys on her tennis team thought so. Including her brother Eric Cann. The tight pants and tennis tops revealed a gorgeous figure. None of them could help but notice the curve of her hips or her perky breasts. Eric least of all. He followed closely behind his sister through the door of their shared family home, discarding his racquet and gear.

Placing his hands on her hips he turned her and kissed her sweaty lips softly. They both quickly glanced around the living room but it was empty as usual.

Emily too was enthralled by her siblings body. She had first noticed his generous manhood during practice as long sweats became tighter shorts.

Neither sibling could resist the illicit temptation of exploring each others bodies. And so they begin doing that. First with quiet touches and fingerings. Then on to more enthusiastic licking and sucking, before full on fucking.

They had developed a routine weeks ago to avoid the suspicion of their parents, which wasn't hard due to their parents rarely being home. First Emily would look around upstairs and if the coast was clear, start the water in the bathroom as if for a shower. She took this time to update the period tracking app on her phone. At the same time Eric would walk though the first floor to see if anyone was home. He was supposed to use this time to relieve himself if he was too excited about the couple's planned activities.

This was the deal Emily and Eric had made, he would be careful about when he would cum, making sure to pull out in time, and she would track her period to avoid dangerous times. They had agreed there could be no accidents that would lead to their parents finding out about their activities. The siblings loved each other too much to risk being separated.

Neither had been doing a good job of being diligent, however. Eric never rubbed one out when he knew his sister was willing and waiting right upstairs, and Emily often got so distracted with the thoughts of Erics cock while she preened herself that updating her tracker slipped her mind entirely. The girl hadn't noticed her cycle was off by almost two weeks now. When the notification popped up telling her that the cycle has just begun, though her period ended weeks ago, she thought nothing of it.

***

At the same moment Emily was receiving the notification, her brothers body completed production of a sperm cell. It was one of millions produced that week, but this one would be the next to travel down his penis. The Sperm floated in Eric's balls amongst millions like it, all eagerly waiting to make the journey.

Emily's tracker continued to deceive her. She believed an egg was about to be released from her ovary, but in reality the Egg had already dropped in to the final section of the girl's fallopian tube.

***

Eric walked up the stairs past the bathroom to his sister's room next door. It's there that she was waiting. The couple began to softly kiss and touch each other. Eric's hands gently stroking his sisters gorgeous red hair and soft neckline. He unzipped the top of her tennis shirt and it fell around her sports bra.

Emily removed her brothers shirt taking time to admire his toned abs and fit body. She then removed her own shorts as her brother was similarly removing his.

The pair reconnected and Emily slowly laid back on her bed, with Eric gently resting on top of her. His semi firm penis came to sit against his sisters slit. Through the thin underwear, the girl was firmly aware of her brothers hardness and the boy could sense the wetness and humidity emanating from his sister.

Eric felt Emilys nipples tighten and harden, even through her sports bra. Unable to stand the temptation, he removed the bra freeing her medium sized, but perfectly perky breasts. Each was topped with little raspberry like nipples. He took his sister's nipple in his mouth and softly kissed and suckled her as his fingers trailed lower on her waist.

He began to touch and stroke her inner thigh, feeling her heat increase. Eventually Eric could see his sisters wetness through her panties. He gently kissed his sister, moving a hand behind her back he lifted his sisters hips and slid a pillow underneath. In the same motion he removed her panties. He quickly removed his boxers before pausing to admire the scene before him.

Both siblings were completely naked and fully sexually aroused. Eric stood fully erect with chest heaving and blood rushing while he gazed down upon his sister. Emily's legs drifted back and forth slightly opening and closing. Her wetness becoming visible and making her legs sticky around her swollen rosy vulva. Her chest was pink as she flushed with excitement.

Eric couldn't stand to wait any longer. He slowly guided his member until it met the entrance to his sisters most sacred part. The siblings locked eyes at the moment when he started to enter her.

Eric paused allowing Emily to thrust her hips up off the pillow, spreading herself around her brother. The mating pair had become fully coupled.

They paused to savor the feeling of one another. Emily enjoying the fullness and warmth her brother provided her with, and Eric lost in the soaking velvety heat of his sister's body.

Eric gently rocked his hips back as his sister did the same. His shaft slid back along her tube, before being thrust forward. The siblings kissed and pulled their chests together as their hips started rocking against each other. Firmer and faster than before, both started to breath hard, pleasure overwhelming their senses.

Emily started to alternate between huffy breaths, giggles, and slight moans. Eric knew this was the sign she was getting close. He needed a better position to keep driving in to her more firmly.

***

Eric placed his hands around Emily's hips, his thumbs coming to rest a few inches from her belly button. Eric couldn't know it, but as he gently squeezed the girls hips during their passion, his thumb was directly on her womb. For the boy it was just a better grip but Emily received a burst of pleasure that made her hips roll forward. Neither could know it but this exact squeeze pushed the Egg sitting at the end of her fallopian tube into her waiting womb.

The churning in Eric's balls increased and his dick swelled even further. The Sperm made it to the beginning of Eric's penis as the last of his precum passed.

***

Eric told his sister he was getting close as he kissed and sucked her hard nipple. A thought raced across Eric's mind that if they were not careful he might soon be kissing these same nipples as they dripped milk.

Emily weighed the risk in her mind of continuing. "My tracker says the cycle has two weeks to peak," The girl thought, "even though I missed one or two days...Yeah, I'm safe." And so she started to form the words that would seal the course of the next nine months. They almost didn't come out, the fear caught in her throat. But the feeling of her brother filling her and pressing on her most intimate parts overwhelmed her.

"Don't stop...Don't stop...Don't stop" she huffed.

She couldn't help it, the girl was in heat. Her hormones completely overwhelmed her senses and the couple continued to gently fuck.

Eric grabbed his sister Emily's feminine waist firmly, drawing her hips up and closer to his. Their pelvises pressed in to each other hard, her labia sealed against the base of her brothers shaft. Eric grunted loudly before starting to fill his sister.

Emily felt a gentle flick-flick-flicking against some part deep inside herself, and heat and wetness begin to spread inside her abdomen. She couldn't resist the ancient biological instincts within her; Emily began to orgasm. Gently at first, but entering strong heavy orgasm as the heat inside her rolled forward. What started as uncontrollable giggles changed to desperate moaning. She felt her abs clench and then her entire core and belly visibly rolled upward, undulating in time as a waves of pleasure traveled from her cervix to her nipples.

***

The Sperm raced forward inside Eric's sister. The cell rocketed down the length of Eric's penis, transitioning from being within Eric's body, to within that of his sister Emily. The vaginal walls continued contractions caused Emily's cervix to dilate and then dip inward, pulling Eric's semen forward and deeper into her reproductive track.

The Sperm was pulled gently forward by the girl's orgasm until it reached the cervix. The heavy orgasm she was experiencing ensured the sperm entered her womb. Spiraling forward, the sperm followed some unknown impulse, like it knew the direction. Almost guided by a magnetic pull.

Emily's egg had moved downward during her gentle fucking from the very top of her womb, drifting slightly to the side. There it continued to slowly descend, all the while emitting a specific chemical marker. The same marker now detected by Eric's sperm.

The sperm honed in, as if the pull of the magnet was getting stronger. Now accelerating as a group of sperm moved away from the rest of the semen within Emily's womb. The Sperm spiraled forwarded locked in on the pull it sensed, guided ever so better than its competition, it met Emily's Egg.

The Egg allowed The Sperm to enter it. Eric's Sperm released its genetic code within Emily's Egg.

The DNA recombined.

The egg came to rest against Emilys soft uterine lining and began to implant itself.

The girl had conceived.

***

Eric held his sister gently, their bodies still connected to the core. She giggled softly as they kissed in post orgasmic bliss. Eric's hands slowly massaged his sisters breasts, he knew his thumbs rubbing against her nipples excited her most. "Emily, I am so sorry I accidentally finished inside you. I just couldn't help it with how our bodies were positioned!" Eric continued to lie to his sister, "I promise I didn't cum that much inside either".

It was at this moment he remembered to actually pull his penis out from inside his sisters organ. They both glanced down as initially little cum leaked on to her short ginger pubes. Within a few seconds a small dollop of semen leaked on to the girl's thigh. Neither knew the vast majority of his sperm currently was swimming inside Emily's womb or too deeply within her vagina to come out.

Emily swiped some of the cum on her fingers, "You're right, it's only a little bit. Today is a safe day for me too! We made this plan so if one of us has an accident, we can rely on the other and still not get caught. I've never felt anything like that. Maybe on safe days you can cum inside me!" This reassured her brother and the two rejoined their embrace. "Don't worry, there's no way I'm pregnant", Emily whispered, as she felt a warm, almost glowing feeling deep within her abdomen.

***

Inside Emily's womb, one cell had just divided in to two. And now two had divided to four. And four to eight. And eight to sixteen. Sixteen to thirty two. Thirty two to sixty four...

***