In order to make the morality of this whole scenario less questionable I have decided to age everyone up by about 4 years from Canon, so everyone who engages in sexual acts during this story is over the legal age of consent. Also, I have decided to make Katara and Sokka good friends rather than siblings, you'll see why later ;) If you have any requests for pairings then please ask and I will see what I can do to make it happen (must be Sokka x ?). Now, for your reading pleasure...

Every 512 years the planets Neptune, Uranus and Pluto form a grand trine in the sky with earth at the centre. During this time, children conceived to the water tribes under the light of the blue moon would receive a gift from Tui & La, blessing them with inhuman strength, stamina and virility. It was upon such a day as this in 80AG that Chief Hakoda and Kya were married, on their wedding night a baby was conceived who was chosen to receive the blessings of the moon and water spirits. His name would be Sokka.

"Come on Sokka, let's go fishing" said Katara as grabbed his hand and began to pull him out of the village and towards the ice floes.

"Ah yes, 'fishing'" using air quotes on the last word, causing a sly grin to spread across Katara's face and they soon made their way to one of their favourite 'fishing' sites. The spot was hidden from the sight and earshot of the village, things which the two young lovers valued highly. Once the men of the tribe had departed to avenge the death of the Chief's wife, Sokka and Katara were left to their own devices during the time of change and maturation that is puberty. They both felt urges and one night, in Sokka's hut they gave in and made love to one another. Although it was Sokka's first time, he seemed to know exactly what to do as if his instincts were guiding him to give pleasure. Katara had of course explored her own body before, however the orgasm that Sokka gave her that night was unlike anything she had achieved alone. The two found it hard to stay apart after that, and snuck off at every possible opportunity to be with each other.

Katara used her bending to remove the ice wall which blocked the entrance to their cave. As they walked through she sealed it up once more, leaving them in an eerie blue light. Walking slightly further into the cave the came to a hot spring and after stripping each other, they lowered their bodies into the water. There was a rock shelf in the spring which Sokka sat on, pulling Katara on top of him so that her knees rested on the makeshift bench. She leaned into him and brushed her lips against his before crashing her lips against Sokka's in a needy way. "I need you so bad right now" she purred into his ear, the airbrushing sensually against his skin. They had had sex last night but Sokka made her feel so amazing that she truly couldn't get enough, it was as though he knew what she wanted before it had even crossed her mind. Sokka held Katara's long brown hair in his hand, pulling it back gently so the smooth brown skin of her neck was exposed. Katara shivered as he began to lazily kiss her neck, occasionally nipping her flesh with is teeth causing her bite back a moan. Soon he moved lower down her body, kissing the hollow of her neck before he began to lick her beautifully pert D-cup breasts. Using the nimble fingers of his right hand he played with one nipple, teasing it gently, whilst he took the other into his warm mouth caressing it with his tongue and occasionally scraping the sensitive skin with his teeth. Katara could never get used to this treatment, no mateer how many times they were together, he always made her breath hitch and the area between her hips grow hot. She couldn't take it any longer, she had to have him.

Katara pulled her body away from Sokka, causing him to look disappointed. "It's time for your reward" She knelt down in the spring, allowing her head to become submerged in the hot water before bending an air bubble around her head. Now she was underwater she could see the part of Sokka which had been poking against her thy as he sucked her breasts. His cock was an impressive 14 inches long and as she wrapped her hands around it, it tensed becoming even harder. Katara rubbed both her small hands along its length, marvelling at its size and perfection. She pulled the foreskin back gently to expose the head which Katara kissed it with her swollen lips. As she began to kiss and flick the tip of his cock, she felt his legs quake with pleasure. By now his long cock was slick with saliva and with a final flick she pushed her head down, engulfing him into her warm mouth. She moved her head up and down, dipping her tongue into his slit as she pushed him deeper into her mouth. His cock soon reached the back of her throat which would have caused her to gag had she not done this many times. Katara swallowed around him and at the same time forced her head down further allowing his cock to enter her throat. She loved the way his cock stretched her throat, it made her feel dirty in all the right ways. Sokka had begun to thrust his hips causing his cock to slide repeatedly in and out of her throat, giving her short chances to breathe. After giving her throat time to stretch around his dick, Katara pushed her head down all the way until her nose brushed against his brown skin. Even below the water, Katara heard Sokka's groan and his cock began to pulsate deep inside her throat. She felt his warm cum flow down her throat into her stomach and was disappointed she had been denied the chance to taste it, he always tasted nice, like honey. Once he was finished she pulled her head all the way off him, allowing her throat to contract back to its normal size.

"Oh my spirits Katara, how did you even get so good at that?"

"Why practise of course" she replied coyly. "Now I want you to fuck me hard Sokka, I can't stand being teased much longer." Sokka picked her up bridal style in his strong arms and stepped out of the spring before laying her on the furs they had previously left on the floor. He spread her long, slim legs placing her knees on his shoulders. With one hand he brushed against her soaked slit and with the other he guided his still erect cock towards her pussy. With a gentle thrust he pushed the thick head of his cock inside her, causing Katara to mewl in delight as she was stretched. Sokka began to thrust slowly, each time going slightly further inside her. His head soon brushed up against Katara's G-spot making her throw her head back into the furs out of sheer pleasure. Soon he was able to fit 10 inches of his cock inside her, she could feel his head pushing against her cervix slowly easing it open. Wrapping her slender legs around his muscled waist, Katara pulled the remaining 4 inches into her pussy with a wet slap as their hips came together. She felt his cock spread her cervix wide and penetrate her womb, the fire pooling in her lower abdomen suddenly faded as shockwaves of pleasure rolled through her body. Her back arched and every muscle in her body seemed to tense, clamping down on Sokka's huge cock. Unable to resist the urge to cum any longer, Sokka began to slam his hips in and out of Katara until cursing and releasing himself deep inside her womb.

Katara felt Sokka's cock pulse inside her, which only served to excite her further. He continued to pound into her frantically as she rode out her long orgasm, slamming her fists into the ground as she screamed his name "Sokkaaaa!" As she did this a huge crack in the icy floor of the cave spread from her fist splitting a nearby iceberg in two. Not that either of the two lovers noticed this. After Katara's orgasm had finally finished, they lay down on the furs together, with his slick cock still inside her, panting from the exertion or reaching their orgasms. They grew drowsy and were on the verge of sleep when the icy wall of the cave was illuminated by a blinding blue light. After dressing hurriedly, they made their way outside to find the source of the light. Standing on an ice floe outside the entrance to the cave lay a boy, no older than 14, dressed in saffron coloured robes and a tattoo of a blue arrow on his bald head.

Sokka recognised the tattoo from tales which his father had told him about the airbenders before they were erased from the earth almost 100 years ago. "I thought all the airbenders were killed long ago?" he puzzled.

"All except one that is"

"You don't mean…"

"The Avatar"