Thor was on the edge of distraction.
By all accounts, he ought to have not a care in the world. He was King of Asgard, the Nine Realms were at peace, his home and adopted worlds safe and protected, and he had his brother by his side (at last!) as his trusted friend and beloved consort.
His days were filled with travel and adventure, seeing to the needs of his people; where danger threatened, the might of Mjolnir together with Loki's clever tricks made short work of their enemies. Evenings were filled with feasts and celebration, rousing times spent with old and new friends, drinking and laughing and passing away the hours. And the nights were filled with the heady heat of their private chambers, fur-lined and veiled by curtains, the crackle of a roaring fire sending golden lights and charcoal shadows across the walls. Loki's heart-stopping silhouette moving over him, his body a pale arc of moonlight in the darkness as he arched his back over Thor's hips, his dark hair tumbling about him.
All should have been well, and Thor couldn't imagine anything that could be better. And yet Thor was steps away from being driven to madness, because Loki had invented a new game.
Thor had learned to accept - he had vowed to be more understanding - of Loki's mischeivous nature. Indeed, it was only a heartfelt relief that the mischief found its outlet these days in practical jokes and little games, rather than unleashing devastating chaos upon the realms. But that didn't always make them any easier to live with, and Thor knew that Loki delighted in tormenting him, in pushing and prodding until he extracted a reaction (just so he could laugh over it.)
Thor's first mistake had been the words. Words were never Thor's strength, and Loki was unmatched at finding ways to twist and bend them to new shadowy interpretations. Thor had caught Loki in his Jotun skin for some reason he could barely now recall, and Loki had been tense and uncomfortable about it, and so Thor had tried to reassure him. All that Thor had said to Loki was that he loved him in every form, and that he would never not wish to fuck Loki, no matter who - or what - shape he wore.
And that had been the wrong thing to say, somehow, because Loki's jaw had tightened in that very distinctive way that it did when he was hurt. Before Thor could sort out what notion had taken hold of Loki now (did he think Thor wanted him to take other skins in bed, for his own shallow amusement? or did he think Thor was somehow implying that Loki was interchangeable to him, and that he cared not for who he held in his arms at night? Thor would never know; he could never make sense of Loki's thoughts) sharp green eyes had narrowed, glinting, and his lips twisted up into a cruel smile. "Is that so," Loki smirked. "Well, Brother, that sounds like a challenge to me."
Ever since then, Loki had made a game of taking on other forms and skins, often at the most inopportune or embarrassing of times. It was bad enough to be twirled around the dance floor by Loki in the form of the Lady Widow, her petite frame making Thor's bulky one look ridiculous by how easily she mishandled him. Worse when Loki perched on the arm of his seat beside Thor's throne in the form of some alarming or ridiculous beast, such as the (what was it called - a rhiningcerous?) that had snorted and pawed the ground all through the delegation from Svartalfheim.
That was offputting, and occasionally embarrassing, but when Loki suddenly shifted shapes in their bed...
He didn't do it every time, of course. A lie lost its credibility when told too many times, and Loki would smile sweetly and be biddable between the sheets just often enough to put Thor off his guard. But then, every now and then, at least one night per week -
Loki had started out by spontaneously taking on the face and form of Thor's fellow Avengers. First Steve Rogers, then Tony Stark, which had been unnerving (but not particularly unpleasant; they were well-looking men, despite the oddness of their hairstyle and clothes.) Then it had been the Lady Widow, which Thor tried not to let on that he enjoyed, and then Son of Coul, which he most definitely did not. Thankfully Loki seemed to have an aversion to Bruce Banner in either of his forms, and neither green skin nor purple pants ever made an appearance.
Then Loki had moved on to more familiar faces, turning up in Thor's arms twice as Fandral and once as Hogun. Once as Sif as well (and Thor had been left deeply confused by that incident as to whether he was allowed to be aroused or not by Loki's parade of masques.) Was Loki pushing the boundaries of Thor's rash promise to burn with lust for him no matter what his guise? Or was Loki testing to see if Thor still held any attraction for others, past loves, and would grow jealous at any hint of infatuation?
Sadly, knowing Loki, it was probably both at once.
"It seems," Loki gasped, his chest heaving with the rhythm of their joined hips, "that you are getting too compla-ah-placent, Brother. Perhaps I should, mmhn, spice up our lovemaking some more?"
Thor groaned, half in dread of what Loki might do, half in passion so urgent it was nearly pain. "Is now really the time, Loki?" he gritted out, sweat streaming down his face.
Loki's eyes flashed in the dimness above him, verdant green above his sharp scimitar smile. "If you court chaos, you wed its consequences, Thor," he purred, and his low rich voice did things to Thor's cock. If he had any sense left he ought to push Loki off him, withdraw from the tight slick embrace of the smaller man's body and retire from their chambers for the night, seeking solace in the dreadfully passion-killing throes of reviewing border reports.
And then Thor made his second mistake: He caved. "No animals," Thor begged him, grasping for at least some lasting shred of sanity. "Not in the bed - the sheets would never survive."
"Hmmmm - you're no fun."
"No monsters, either," Thor added on, seizing the moment of acquiescence on Loki's part. It helped that he knew well just how vain his brother was; even in his ongoing campaign to unsettle Thor, he seemed reluctant to take on any form that was actually ugly. "I do not wish to grapple with either a draugr or a troll in my very chambers."
"But you're so very good at... grappling," Loki said. "Very well, since you insist -" and the glee with which he accepted Thor's terms sent a warning chill down his spine.
He was so close. Thor closed his eyes tightly, biting down on his lip as cold sweat ran down his back, a warning tightening in the muscles of his belly and thighs. He heard and felt and smelled Loki change, his familiar skin overtaken by another, and the tingling wash of magic over skin so intimately joined was more arousing than he would ever let Loki know.
"Oh - oh, my king - you are so hard and hot inside me, so strong and manly -"
He wasn't going to look, he wasn't going to look - Norns curse it all, he was so close -
"Oh, my husband! Oh, my king! Fuck me! Fuck me harder!" Loki screamed out above him in a terribly, terribly familiar voice. "Fill me with your seed! Plant a child in my belly! Let us make an heir to the throne tonight, Father of Asgard!"
And Thor made his worst mistake of all.
He opened his eyes and looked.
And for the rest of his days, Thor would be forevermore scarred by the image burned into his brain of Queen Frigga's face and silhouette perched wantonly over his hips, golden hair spilling over her matronly breasts.