The first thing the strange other Lance had when he appeared in the Red Lion with their own original Lance was, Keith is told, “Oh hey I know what this is! I remember this!”
This was something everyone had no choice but to believe, because there was really no other explanation for a second, ten-years-older-than-ours Lance showing up out of literally nowhere after an explosion surprised the entirety of Voltron and the Galra they were fighting by coming from the wrong end of a Black Hole.
The other Lance, Keith was fast to discover, was incredibly tall, incredibly confident (in a relaxed sort of way that only served to make him more attractive,) and above all else, completely unconcerned by his current temporal displacement. Apparently he remembers how the older Lance that HE had met got home when this had happened to him ten years prior, and the concept of time was, he assured everyone, completely reliable in its ability to stay exactly the way its meant to.
What Keith had had trouble understanding was what any of that had to do with him, and why, when Lance had seen him, he’d grinned lewdly and waggled his eyebrows at Keith to purr, “Ooh, that’s right, looks like this is finally gonna come full circle, too. I’ve been waiting for this for a long time, you know.”
“This,” as it turned out, was luring Keith to a nice private place to seduce the ever-loving hell out of him. Uhhh… If Keith was gonna be totally honest here, it was not hard. He already had some weird kind of crush on the other paladin - or at least, his version? And this Lance was taller and sexier and more mature and basically just so much extra , like, Lance amplified by… well, ten. Ten years of intergalactic war was, uh… a good look on him.
And he also had ten years more experience in other matters, which Keith really should have thought about before he let it go this far. Keith was so, so fucking far out of his league. How, you ask, did he know he was in over his head? Because before tonight, Keith hadn’t even known he COULD come three times in one hour, much less think to expect all that and more .
“I, I can’t,” Keith pleaded, broken even to his own embarrassed ears. “It’s too much, there’s no way .”
“Oh Honey, of course you can,” Lance just cooed in return, nuzzling Keith’s ear and petting the hair out of his face. “I was right about all the other things you thought your body couldn’t do, wasn’t I?”
That, Keith reflected, was certainly true. He hadn’t thought Lance was serious when he claimed Keith was so adorably small that he could hold him up and fuck him while standing but lo and behold he’d done it, Keith’s weight supported only by the hands he’d looped around the back of Lance’s neck and the cock he was riding. He had thought his legs wouldn’t bend that far, but no, Lance had spread Keith open ankles to ears and fucked him so hard Keith couldn’t even concentrate to see the handsome face hovering inches his own, everything a blur of teary wet brown and gray. And he hadn’t thought prostate orgasms were a thing, but Lance had already given him four so far, each individual one feeling like a supernova exploding in Keith’s nervous system and leaving him shaking and incoherent for minutes after.
“I… I don’t know,” Keith ended up stuttering, trembling in Lance’s strong, battle-scarred arms. “I mean, you were, yeah, but…” But every nerve in his body was on fire , he was sore and aching hard and he couldn’t keep a single thought in his head straight anymore and letting Lance fuck him again sounded like it was just too much, way too much, he’d overload and combust until there was only ash and jizz left.
Lance smiled warmly, eyes filled with an affection Keith couldn’t comprehend as he continued petting Keith’s hair. “It’s okay, sweetie, you’re allowed to say no. I can suck you off to finish you this last time, huh?” A kiss to Keith’s forehead that made him tremble and blush more than anything else tonight so far. “I was just having so much fun, wanted to show you all the things you and I will do together someday, you know? I didn’t get to be there for my Keith’s first time, wanted to make up for it by showing you how good we’ll be for each other.” A lewd and almost shark-like smile, “Wouldn’t want you to give up on us just because of how terrible my nineteen-year old self was in bed, after all.”
Keith’s heart was just about bursting out of his chest, for more reason than he knew of or could really understand. He didn’t know if he even really believed all the things this Lance was saying - not that he and his own Keith weren’t in love, but rather his confidence that Keith’s own life would turn out the same way. How was he supposed to react to the information that’d he was going to have a decade-long love affair with a guy he’d only just barely made friends with in the last few months?
Lance was kissing down Keith’s chest again humming about letting Lance take care of him, and Keith just didn’t know . He didn’t know what to think about anything, could barely think at all, but… But he was sure that this was the sort of opportunity that wasn’t gonna come by again. Even if he and Lance really did end up together, hadn’t this version just said himself that their sex wasn’t good at first? Because the sex he was having right now was quite frankly Earth-shatteringly good.
“No,” Keith found himself saying, voice still humiliatingly thin. “No, I want you to fuck me again. I can take it.”
When Lance sat up to look down at Keith again, his smile was somehow warm and radiant and absolutely terrifying all at the same time. “That’s my good little kitty,” he smiled lovingly. “Never settle for anything less than everything, do you?”
Keith shuddered again, this time half out of anticipatory excitement. Lance’s hands were on him again, large and strong enough to easily direct Keith’s body however he pleased as he pulled him to on his knees so he was kneeling on the thin mattress. “Here, sit up, on your knees. I’m gonna take you from behind this time so you can just lean back against me, okay?”
Keith closed his eyes and nodded, too-aware of every touch of his skin and shift of the bed as Lance positioned himself behind Keith, pressing his broad hair-covered chest directly against Keith’s back as pulled their bodies close to each other. His knees were weak and shaking but like this they weren’t actually really supporting his weight, which was good considering Keith didn’t think his own thighs would be able to hold him up for very much longer.
Lance was kissing the back of his neck now, purring more honey-sweet words of encouragement into Keith’s hair as he aimed the tip of his cock into Keith’s loose and thoroughly abused asshole.
Oh god, this was the part Keith was afraid he couldn’t handle. Lance’s cock was enormous and he’d already been fucking Keith for nearly two hours now, so the pain of overstretched muscle was expected when Lance’s soft tip slowly pressed inside. But it wasn’t as bad as he’d thought it might be, the slight burn not much more than the first time Lance had pushed inside tonight and way more terrifyingly intense than the pain was the pleasure. Oh god, how did it still feel so good ? And how the fuck was Lance able to brush against Keith’s prostate on every single push inside no matter what the angle? Never underestimate a professional sharpshooter, holy shit.
He didn’t move right away, just stayed seated deep deep inside Keith for a few long heartbeats to make sure his body really could handle the strain. And when Keith gave no indication he in any way wanted Lance to stop or pull out he began to move, slow and gentle little rocks just a few easy inches in an out in a perfect lube-slick glide.
“Oh god,” Keith whined again, because even just this felt too intense at this rate. He’d come so many times and he didn’t understand how his erection hadn’t flagged the slightest bit, just continued to pour out a steady stream of more precome than Keith was aware his body could produce.
Lance just hummed again in a purr of contentment, one arm wrapped around Keith’s shoulders to hold him to his chest and the other at Keith’s hip to prevent him from jostling too far away from Lance’s hips with the force of his thrusts.
They stayed at that sedate pace for a few long minutes, and Keith finally relaxed to let Lance bear the entirety of his weight while he bit his lip and let himself sink in to the wonderful feeling of being so full. Lance felt so fucking good and the constant massage against his prostate was just… indescribable. It was a sensation that took up Keith’s whole body starting deep from within his guts, a pressure almost like really needing to pee but also somehow totally different while being just as distractingly intense.
“So good for me, baby, you’re being so good,” Lance praised as he slowly lowered himself into sitting down, taking Keith with him in a single fold of his bent knees. Somehow he felt even deeper now, reaching all the way to parts inside Keith he hadn’t even known existed and gradually speeding up his thrusts to fuck Keith harder and harder.
Keith’s jaw fell open and a stream of whines poured out at the same rate as his leaking cock. He couldn’t have stopped them if he’d tried and couldn’t have told you how loud he was being if he’d been directly asked, far too focused on the thick cock inside him. “Harder,” he found himself demanding - no, more like begging, hips working down desperately to take charge some of his own pleasure. “Give me more, please, Lance, please !”
“So cute,” Lance laughed, unwinding his arm from where it was locking Keith in place to grab a steadier hold by curling around his bicep. “You’ve never changed, always want everything I can give you and more.”
To spite the teasing note to his voice he was already complying, using the hand he had on Keith’s hip to completely take over the roll of his hips, practically dragging Keith down onto his cock at the same time he bucked up into him. “I still can’t get over how small you are,” Lance was crooning delightedly. “You’ve always been solid muscle so you end up weighing so damned much when you get taller than this, I’m not used to fucking a Keith that isn’t a brick house.” He let go of Keith’s left arm just long enough to squeeze his thigh instead. “And you’re so soft ! I can’t believe you’ve even still got a little bit fat on your bones, you’re so easy to fuck I feel like I could go all night.”
Keith felt his face heat into a blush, humiliated and aroused at the same time. He managed to croak out the word “Pervert,” in between his raucous moaning, to which of course Lance only laughed.
“Let’s get that cute voice of yours singing for me again instead of sassing me,” Lance just answered with an audible grin, delivering one sharp slap to the side of Keith’s thigh only inches below his ass. And that’s when he stopped playing with Keith like and started fucking him for real, hard thrusts that drove his cock deep into Keith’s throbbing ass and had Keith’s entire body bouncing on his lap.
Keith did indeed sing, voice reaching humiliating pitches known previously only to birdkind. He couldn’t help it - somehow no matter how hard he fucked Keith he always hit his sweet spot dead on, each of his deep powerful thrusts gliding right over Keith’s prostate and making his whole body shake and go weak, able to feel nothing but sex sex sex from about his belly down to his toes.
They were both sliding backwards as Lance lied down on the bed, Keith’s legs bent at the perfect angle that he didn’t need to hold him in place to be fucked anymore. Just held on to both of Keith’s stiff arms where they were locked solid around his ankles to keep himself upright, spine bent in a backwards arc like a taut bow because the second he tried to relax and fall into Lance something about the angle changed in the bad way and Keith just lost all the good feelings they’d been working so hard to drive Keith insane from and the strain on his shoulders was totally worth bearing if he stayed this close ...
Close to what, though, Keith wasn’t certain. Coming, maybe? There was something about the constant drive against his prostate that made that impossible to identify, each orgasm so far had taken Keith completely by surprise, unstoppable and intense as a tsunami. There was no way to know when he was gonna come again and no choice but to just sit back and enjoy the ride, feel and want for nothing but the overwhelming pleasure of the hard cock inside of him.
“Mm, honey you’re so good, being so good for me,” he could only barely hear Lance’s compliments over the constant noise of his own moaning. “Keith, baby, gonna show you everything, gonna prove how good I can be to you. Been waiting for this so damned long, Keith, waiting for my turn to totally wreck you. Prove to you no one will ever love you the way I do.”
The words were still completely unmissable, made his heart pound and his limbs shake for reasons that didn’t have anything to do with sex. He felt his arms collapse under him, landing with a sweaty flop onto Lance’s chest. Lance just giggled again, hugging both long arms around Keith’s shoulders and rolling them both over to pin Keith to the bed.
Somehow, being trapped between the soft mattress and Lance’s tall body was warm instead of smothering, a confusing kind of comfortable that made Keith feel oddly… safe? It was still Lance , after all, even if it was a strange foreign version of his friend. Lance would never do anything to hurt him, not really.
Lance wasn’t reaching as deep anymore like this but he was kissing Keiths neck, slowing down the previously punishing pace to rock Keith gently into the bedsheets. Not for the first time tonight Lance had turned this encounter that Keith was so desperately trying to keep casual into some strange form of love-making, confusing Keith’s head and heart and body all at the same time until he wasn’t even sure if he was still sobbing from pleasure or for some reason, like… because actually crying, here. Or both?
Everything was too confusing and too much and too soft, especially with the way Lance kept kissing his neck and hair an cheeks and whispering sweet, sweet nothings that he didn’t know if they were even for him or some version of himself he wouldn’t be for ten years yet but every word made him ache .
And yet, somehow, even with the pathetic onslaught of emotions it was still impossible not to relax into Lance’s hold. He was surrounded by warmth on all sides and the pressure against his prostate was now accompanied by the large hand that had snaked its way under Keith’s body to wrap around his cock, the first time his aching erection had been properly touched all night.
“That’s right, baby, it’s okay. I’ve got you, Keith, you can let go now,” Lance encouraged softly, stroking Keith in time with his steady thrusts. “Come for me one last time, sweetheart, it’s time to let everything out.”
Keith, most likely, made a noise. And this noise was, most likely, completely humiliating and pathetic. But alas, that could hardly be helped, because he was already obeying and the orgasm that had started electrifying Keith’s body was the singular most overwhelming feeling he’d ever experienced in his life . Wave after wave of sensation, starting at his groin and rippling out to shake through his whole body as Keith screamed and shot more semen than was physically reasonable into the bed below him. It seemed to go on forever, minutes and minutes long, not stopping even after Lance had pulled out and even through the time it took him to jerk himself off onto Keith’s back.
It was hard to say when exactly his orgasm even ended, considering Keith didn’t regain any ability to move his limbs for several long more minutes. Just laid there panting while this Lance stroked his hair fondly, wiping a damp towel over Keith’s tingling skin, and he wasn’t even down from his high by the time consciousness slipped through his fingers and Keith fell into a deep, heavy sleep.
When he woke up, this Lance had been gone for hours. And his own current Lance? Well… That was a situation Keith was going to have to think about for a while.
Meanwhile in the future, a twenty-nine-year old Keith was glaring with impatient irritation at his fiance, arms crossed over his chest.
“W-what?” Lance asked defensively, withdrawing on himself like a threatened turtle. “You can’t be mad at me for this, you’re the one that did it FIRST! Even if you could possibly twist the logic of banging a younger version of you into being cheating, I still would have had to do it because time said I already DID! We can’t break time, Keith!”
“Yeah sure,” Keith agreed sharply, not softening in the least bit. “But I HAVE been waiting ten years to ask if it was REALLY necessary you go THAT DAMNED FAR, Lance?! Did you forget that I would know what happened?! I was NINETEEN!”
“I was just trying to impress you!” Lance defended helplessly.
“I couldn’t sit down the next day, Lance!” A pause. “Well,” Keith admitted, “You DID certainly leave a good impression though, I’ll give you that.
“S-see?” Lance laughed nervously. “Then, no one did anything wrong and we can, uh… Finally put this whole mess behind us.”
“Except for the part where there must be some original timeline where you got sent back into the past, and then without having any idea how or if it might impact the space-time continuum, decided you really needed to bang me as a teenager there while you had the chance.”
“...I feel like it’s healthiest not to think about that.”