Written to Fader - The Temper Trap, crosspost from AO3
Thor counted down the days to those weeks in the middle of the summer when Loki would be fertile and insatiable with great delight. Loki would often wake up in the morning to find Thor staring gleefully at the calendar as he tapped the days before the first red circle and counted aloud to himself; sometimes he would shout out a random number and watch in amusement as Thor would shoot a frown back at him over his shoulder and have to start over from the beginning. And before Thor came to bed at night, he would go over to the numerous calendars on the wall and cross out another day with a huge smile on his face.
It was absolutely infuriating to Loki. Thor simply could not be distracted to forget to cross off a date, no matter how much Loki whined and spread his legs and rustled the bedsheets. Loki's hopes of getting Thor to lose track of the date were dashed again, and again, and again, and no amount of pouting could get Thor to toss the calendars.
Loki had even gone so far as to try to torch them, but Thor had run in the instant he'd set the page afire, and had doused the flames with his cape. He'd given Loki a disapproving glare, which he'd learned from Odin, probably, and ever since then Thor had taken to carrying a pocket calendar the Man of Iron had given him. It came complete with an electronic database and an alarm system that would make the most hideous beeping if anyone but Thor tried to activate it, and Loki supposed he'd spent far too much time making mischief on Midgard, because the Man of Iron had somehow managed to put safeguards on the device that sent his own magic flying back at him whenever he tried to toy with it.
He took a brief moment to curse Anthony Stark and his future progeny before setting the calendar firmly down on Thor's nightstand and glaring at it as Thor came out of the bath, a towel slung around his hips.
Thor smiled in amusement, dripping water all over the stone floor.
"The Man of Iron truly is brilliant, is he not, brother?" he inquired as he pinned Loki to the bed, dripping all over him.
Loki just harrumphed and allowed Thor to press kisses to his jaw.
"Thor tells me that you plan to have another baby," Frigga said to Loki one day in the nursery, where he was comforting a crying, teething Jörmungandr. The baby serpent had already managed to chew through his crib, the royal nursery's curtains, and about half of the thick mattress Sleipnir liked to sleep on. His fangs were coming in quickly, Loki observed; Laufey had been to visit his grandchildren the other week and had proudly told Loki that Jörmungandr, when he grew up, would be the perfect leader for a rebellion staged in South America.
"And he'd have friends!" Laufey said, looking terribly excited. "I have heard reports of terrifyingly great serpents called Anna Condas. Of course, I do not approve of their names, but little Jory here could mate copiously with them and could take control over Midgard with his spawn!"
Loki had had to politely decline the offer. "Little Jory" glared at Laufey with his beady eyes, and promptly bit his hand when he reached out to pat his head. Laufey only smiled indulgently.
"Thor is very eager to have a child, yes," Loki agreed as he patted Jörmungandr's head. The little snake had fallen quickly asleep after gnawing his way through a cubic foot of ice Odin had brought back from Jotunheimr. "However, I am rather doubtful of his potential conduct as a father."
Loki had the worst fears about Thor holding their future child upside down, not supporting its neck, tossing it about like a rag doll, and the like. Frigga only smiled, and gently patted Loki's arm as he laid Jörmungandr back in his crib.
"I am sure for the child he can learn to be more careful," she said. However, right at that moment, they felt a great bang underneath them, accompanied by Thor's roar of delight and the distant crack of thunder. Frigga only smiled and rolled her eyes.
"Perhaps you will have to teach him," she amended as the tapestries on the walls shook a little bit. "He is...rather rough around the edges."
Loki scoffed. That was quite possibly the understatement of his lifetime.
Frigga looked at him with delight in her eyes, and Loki sighed. It was evident Frigga was eager for tiny grandchildren - preferably human-looking, and not snakes or horses or dragons. Loki could understand that.
There was another boom of thunder, and Jörmungandr woke up, writhed around, and when he saw Loki, unhinged his jaw and started wailing, much louder than a baby snake had any right to. Loki huffed in annoyance and picked him up again.
The weeks leading up to his cycle were unseasonably hot, and Loki took to walking around the cool stone halls of the castle in only a linen shift with a paper fan and jugs of water close at hand. Thor followed him like a dog, and Loki would smack him over the head with the fan occasionally, but that didn't deter him one bit.
The days right before Loki's heat were rather irritable ones, and Loki took to snapping at anybody who looked at him for longer than a few seconds. He was well aware that he constantly had a blush dusting his cheekbones and that he was giving off a rather pervasive scent of cinnamon and peppermint, but they didn't have to stare so! One of the Asgardian toddlers had even waddled up to him one day, sniffed him, then licked his shin.
After being shooed away, the little blonde child squinted up at him and claimed that, "You smell like a cake, Pwince 'oki."
And then there was the matter of Thor, who looked at him wolfishly and laid his hands on his hips every chance he got, as if feeling for the widening of Loki's body. And no amount of shooing or swatting would get him to stay away. Sometimes Loki wondered whether it was actually Thor who was the insatiable one.
And then, of course, the morning of his cycle dawned. The itch woke him up, deep seated inside his belly and rapidly crawling up his spine to tingle through every nerve ending in his body. The day was horridly hot, though that might just have been Loki himself, and Thor was just a great mound of heat lying uselessly beside him. Loki dug his heel into Thor's ribs, waking him up mercilessly.
Thor looked at him for a few moments, blinking blearily up at him through a thin film of sleep. "What is it, brother?" he mumbled sleepily, yawning.
Loki climbed on top of him, grinding his erection into the junction of Thor's thighs, and Thor's eyes widened as he took a deep breath heavy with spice, and Loki smiled triumphantly as Thor's pupils dilated. It was reassuring to know he still had some modicum of control over the man; he wouldn't be in his right mind later on when the heat consumed him to appreciate it then. He hadn't bothered to fully dedicate himself to any one gender, and his cunt was aching, hungry, dripping, his clit swollen with arousal, partially hidden by his cock.
Thor smiled obligingly and gently rested his hands on Loki's waist as Loki impatiently, with clumsy fingers, undid the drawstrings on Thor's cotton pyjama pants and tugged them down. Thor was already hard, Loki's scent and musk and heat infectious in its desire.
Loki's entrance was already damp with slick and heat and wet, and he pressed himself down roughly onto Thor's cock, wailing at the friction. He clutched tightly around the base of Thor's erection, and Thor moved his hands to Loki's hips, urging him along.
Thor bucked his hips up as Loki frantically ground down, and with a lovely little cry of surprise, his mouth shaped in an "O!" Loki spilled himself across Thor's stomach, spasming in the cradle of Thor's thighs.
With a rough groan, Thor flipped them over, hitched one of Loki's legs across his shoulders, and continued to pound into his brother, each thrust deep and rough and utterly delicious. Loki clutched sweaty fingers into the bedsheets and sobbed as Thor reached down, grasping his erection and flicking a careless thumb over the head. Loki's voice became a chant of "Again!" and "Thor" and "please," although if you asked him, he'd claim he never said the last one, and Thor was more than happy to oblige.
It seemed ages and multiple orgasms later before Thor finally bucked up roughly into Loki, blunt fingernails digging into the inside of Loki's knee, and spread himself hot and warm inside him. Loki screamed, coming for what seemed like the millionth time, his cock red and raw and aching, as he felt Thor's seed smooth and burning against his insides.
Thor pulled out gracelessly, and before Loki had time to adjust, pressed his still-hard cock into Loki's cunt. Loki barely had time to suck in a breath before it was driven out in a sharp cry as Thor began to rut and grind against him, and Loki swore he could feel thunder crackling through his veins and spreading electric heat through his lower abdomen. Loki whimpered breathlessly and allowed Thor to lift his hips up bodily and thrust and thrust and thrust, sliding Loki against the sheets.
And when one of Thor's hands reached around, gently pressed a tentative thumb to Loki's swollen clit and rubbed, Loki gasped and shrieked as he clamped down around Thor's cock, his clitoris spasming and twitching helplessly against Thor's questing fingers.
Thor dragged him through that cycle roughly too many more times to count, and all Loki could do was allow the heat to pound through his veins and let the sheets slide frictionless against his skin over and over and over until finally, finally, as the white sparks began to crawl over his vision, Thor spread slick, wet heat into him again.
Thor flopped down bonelessly next to him, sucking at the air and flinging one broad arm around Loki's still-quivering shoulders. The scent of cinnamon and peppermint was still heavy in the air, punctuated with the sordid smells of sex and arousal and sweat.
Loki could feel Thor's warmth quickening inside him, the virile royal seed eager to find a place to grow. He wondered when their baby would come, what it would look like, if it would have the fair skin and blonde hair of the Æsir or the blue skin of the jötnar. He was sure Thor wouldn't mind, either way.
"Loki, love," Thor's voice was rough and winded, "has it taken?"
Loki only smiled, closing his eyes in exhaustion, ready to get some much-needed sleep before the next bout of heat would kick in in a few hours.
"Quite possibly it has," he agreed, "rest now, we'll need it for later."
Thor spent the next few days drifting between Loki's chambers and the kitchen for food and drink, which he carried back. Everywhere he went he was draped with the scent of cinnamon and peppermint, and Frigga looked fondly on as her elder son carried fourteen hams, five racks of lamb, and three pitchers of fruit and water back to Loki's rooms.
Loki had taken to stuffing the vibrator Thor had bought him into himself when Thor was absent, either scraping the caked sweat and come off his body in the baths or fetching more food for Loki. They were going through the batteries at an alarming rate, but Loki was oh so lovely with his face flushed, reaching out for Thor, his fingers sticky with come and fruit juice, as the device inside him buzzed long and relentlessly against his insides and wrung orgasm after orgasm from between his twitching thighs.
And when the week was finally over, when Loki shuddered down to reality from the pleasurable haze he'd been in, Thor smelt something different. The peppermint and cinnamon still hung around Loki loosely, but there was something else also. A hint of lavender, a blossoming of some exotic flower Thor couldn't identify but which he would later recognize in a pot of orchids.
And Thor looked at Loki wearily, and Loki only smiled, took Thor's hand, and laid it on his lower belly, watching Thor's tired features light up with hopeful joy.