It was safe to say that he was avoiding you. Sure, doubt had crept through your thoughts for the first week, second week and even into the third, but every thought that tried to convince you otherwise fizzled away when you simply let the conclusion come to its end: he was absolutely, positively avoiding you. If it wasn’t for the fact that your job hadn’t been entirely set on keeping an eye on the Autobots and the children in their care, it may not have come off so obviously--
Well, if you weren’t otherwise obligated by the military’s orders, you probably wouldn’t have even met them, huh?
It doesn’t sit well in the pit of your stomach to know that Optimus is avoiding you. You worry first that his always-constant missions is keeping him busy, and then perhaps that there are issues that you couldn’t hope to understand with his people, his race, and then the worry boils even further into the fear that he’s finally found you worthless of his attention.
It’s the last thing that scares you the most.
There’s no secret, attempted or otherwise, for the relationship you shared with him. What had begun as a professional task had become a friendship, then a bond, and then something deeper--it had blossomed into something innocent and wonderful and all shades of affection that had your heart singing every time he said your name in his powerful voice.
Dating was too...casual of a term to use. Partner? That was too...wrong. There was no proper label for the relationship you and Optimus shared, but it was a bond strong enough to know when, suddenly, he had begun to avoid you. Begun to find reason to leave the room, to escape a conversation, all the while with a look of unease and frustration on his face that made you feel...scared, in a way.
So you did what any mature adult would do in a situation like that: you sought Optimus out yourself.
It wasn’t exactly a hard thing to do, considering the fact that your job all but required you to know where they were at all times, but it was still a bit of a chore to nail down the Autobot leader. The base was huge, built for beings that were at minimum a dozen feet tall, so it took some snooping and perusing from room to room to figure out where Optimus had settled himself for the evening.
Of course, you found him in one of the science labs; your science lab, to be precise, the very one that had been built for you to take all of the information down needed to satisfy Agent Fowler’s constant need for information and updates so that he could tell others with the need-to-know that the earth wasn’t in any particular danger to this particular faction of alien lifeforms. Well, it was among some of the reasons for having the lab to yourself, though you didn’t understand a lot of the information you gathered and--
It didn’t matter right then. None of that mattered.
What did mattered is, when you stepped into the lab, sectioned-off partially from Ratchet’s work area, you found Optimus standing over a console to himself. He seemed to enraptured in his own thoughts to notice your entrance.
“So this is where you’ve been hiding out until I go home, huh?” The question comes from your lips with more disdain than anger; it makes the autobot leader jump regardless in surprise. “Clever, I suppose--A little easier to hide when you’re only like, 8 feet tall when compared to, what, 30?”
Optimus turns his head to quickly confirm the face to the sound of your voice. Though you see momentary fear in his optics, he doesn’t try to hurry out the room or sputter out a very sudden and very fake-sounding excuse to leave. He lets out a sigh (do Cybertronians need to breathe?) and taps a button on the console to exit out of a series of hologram readings.
It’s a little disorientating to approach him when he was so much closer to your own size, but not enough that it keeps you from crossing your arms in the ever-growing need for an answer--an answer to a question that practically burns your lips as it leaves them.
“Why are you avoiding me?”
It comes out a little too emotional. Something about the sound of the words when you speak, or perhaps even the way your body feels tense and loose all at the same time--it makes Optimus look hurt, genuinely hurt as he opens his mouth and then, just as suddenly, he closes it.
It’s obvious that he’s not going to reject the accusation, but that’s not the response you want from him--you just want an answer, an honest-to-god answer that could sate the gnawing anxiety that had been chewing on the back of your thoughts for weeks.
“Optimus?” You take a step closer to him, head tilted and brows knitted in concern. “I just...want to know why, is all.” A blip of anxiety crosses your mind. “...Did I do something wrong?”
“No,” The leader responds firmly and quickly enough to the suggestion that it is at least a mild comfort. He takes another breath and slowly meets your gaze with his own. “I...have been avoiding you, I will make no attempt to deny that, but it is of no fault other than my own.”
“That doesn’t really answer the question though,” You say, hands gesturing in hopes that it would effectively communicate your exasperation with the moment between you both. “I mean I--...I thought we were....” Again, there is no real term that felt right, no name to call the two of you that would describe the feelings you had for him.
So you take a slow breath and let it out all the same.
“...I love you, Optimus.”
It’s not the first time that you’ve said that to him, but it’s still careful territory. It’s unknown and confusing and scary and absolutely wonderful all at the same time. Seeing his response, the pause in his words and the careful focus of his eyes on you--
You take a step closer, just a few short from being able to reach out and touch him.
“I don’t know what’s bothering you, but let’s work this out together?”
Another step, and then another, close enough that you have to lift your chin and face high to keep your eyes locked with his. Though the mass displacement could work wonders on making him slightly more approachable, it still kept him hovering above you and yet, he still looked so small in the moment. So unsure. So worried--
Of what? What could he, the leader of the autobots, be afraid of?
Optimus averted his gaze after a moment.
“I…” he tried to find the words. “I do not try to hide nor suppress my feelings for you in kind. It was irresponsible of me; I thought that taking time to think over the problems myself would yield insight to a solution for how to...proceed.”
Optimus looked even more unsure, almost flustered if there ever was a way for a ten-foot-tall robot to. He had no ability to blush, no blood to rush to his cheeks, but you saw it all as clear as day: he looked awkward and unsure of himself.
“For Cybertronians, we have reached a level of our bond where many would have already…” Optimus tried to search for the word, but let out a growl as he could not find it. “We would have already...interfaced.”
“I think the word you’re looking for is ‘sex’, in English at least.”
Was he...worried about sex? About how to have sex with you? The thought seemed rediculous, something akin to what a teenage boy might feel like with the thought of his first post-middle-school crush, but it’s...not at all what you expected Optimus to feel like. But the more you thought about it, the more it made sense: you and him were entirely different species, there was no telling the differences and challenges that could come up for what otherwise seemed like such a carnal activity.
Nevertheless, Optimus nodded, reaching out one of his hands to cradle against the side of your head.
“You are not a Cybertronian,” He said slowly. “But...there are still some possible issues that may come in sharing a bond with me.”
“I understand if we’re not compatible to have sex, Optimus,” The words flew from your mouth faster than you could stop them, relief and amusement mixing together as you all but nuzzled your face into his gentle palm. “That’s the least of my worries, really, because-”
“We are actually too compatible.”
It took a moment for the simple sentence to sink in.
Optimus looked that same brand of awkward-and-unsure again. He looked like he wished he could do more than just avert his eyes--it was the look of someone who was trying, and failing, to look abysmally small.
“...There is a possibility, due to the fact that I am a Prime,” Optimus took a moment to weigh his words as you felt his thumb brush over your head in a careful sweeping motion. “-That I will be able to sire a sparkling within you if we had ‘sex’, if you will.”
In all honesty, it takes longer than you’d like to admit to parse all the words together and filter them through your thoughts for a meaning to come out the other end. It’s not that you don’t follow what he’s saying, it’s just that the concept is far enough beyond what you expected him to say that it’s nearly foreign to you.
Sure, it’s not as if you don’t understand enough to know the basics of his people, the importance of Optimus as a leader and the fact that ‘Prime’ was not simply his name, but a title bestowed upon him that came with a certain level of power and influence and a million other important things your brain couldn’t begin to recall at the moment.
But he was telling you that he could get you pregnant.
The look on your face must have been hilarious, in hindsight, but it was surely enough to make Optimus feel more than a passing need to explain it all to you in a bit more detail.
Something about his spark being powerful, something about humans being exposed to energon being receptive carriers, something about a million things and it all came back to one detail:
The thought had never crossed your mind; hell, the fact that you and him may never have something resembling sex had been the biggest worry, but this? This was huge, this was different.
This was amazing .
Nevermind the scientific wonders that the opportunity could present, it was a relief, a wonderful relief, that Optimus’ only worry that had kept him from talking to you was a fear that he could get you pregnant? Jesus, you were scared that he was bored with you, no, maybe even hated you, but he was scared about having a baby?
“I don’t even know how that’s possible,” You said, reaching a hand up to touch his own against your face, to nuzzle and kiss his palm because god , you were scared of something so much worse. “-but you didn’t think I wouldn’t be happy?”
Optimus blinked, even though it was yet another unnecessary gesture. The confusion on his face was obvious. You felt your brows knit again, this time in amusement that the concept, the simple concept that you may not actually mind having his child--it seemed alien to him.
“Would there be something wrong with carrying your...sparkling?” The word felt a little odd on your tongue. You turned your eyes up to catch the softly-glowing blue of his, met his gaze for a few moments so that he could understand the meaning and genuine depth behind your words.
And then, once the surprise was gone, once the pieces began to click together, you could feel the heat in the air. You could feel Optimus’ gaze turn into something deeper, something almost distinctly predatory and hungry.
And the shiver that moved down your spine was delicious .
Despite the vast differences between both of your species, sex was still more-or-less the same. The heat, the desire, the hunger that seemed to take hold of your thoughts--it all seemed mutual as could be. It was a wonder to experience it, feeling soft and awkward like a teenager all over again, to feel the rush as you and Optimus sought for the privacy of an unused room, one that wouldn’t have someone barging in on the intimacy between you.
“And you’re certain that-” Optimus can barely get out the question before you’re shushing him with a kiss, feeling the strength in his arms and hands as he held you up and against him.
“ Yes. ” The words fell like rushing water from your mouth when the two of you parted. “I want you to fuck me, Optimus--” You could feel the gentle shiver through his limbs as he filtered your words. “--I….I want you to put a sparkling in me.”
And that must have been a breaking point. It must have been a dozen breaking points, since the autobot leader could barely seem to keep himself contained and still as he pressed a kiss to your lips again. It was harder this time, more passionate and less restrained and yet with every ounce of love you wanted from him.
His hands cradle you against his chest when he finally finds a place to lay down--an unused berth in the empty room is more than good enough. He holds you to his chest as he moves--he may be a fraction of his original size, but he is nonetheless immense in stature and strength; it wasn’t a secret that a misplacement of his weight or strength could hurt you plenty.
It was exhilarating nonetheless, your legs wrapped around his thin waist and his body hovering over yours as he stripped one layer of clothes after another from your body. You’re almost worried for the touch of cold metal against hot skin, but when you’re bare and naked beneath your partner he felt anything but; he felt so warm, so blissfully warm against your skin that you let out a soft moan for that sensation alone.
“Are you alright?” Optimus asked. His voice was soft, hushed almost, and it beckoned forth a blossom of heat from your chest at how genuinely nervous he sounded. “I’ve….looked into the process with humans--it’s much the same style of reproduction of Cybertronians and--” His words became a bit of a jumbled mess by that point, terms and sounds blurring into one another that only seemed to make his babbling mess of awkward nervousness worse.
But it was cute; it was so damn cute that you almost felt bad by cutting him short.
For as much as you try to sound soft and whimpery, the noise that comes from your mouth is less forced or acted than you tried for. Your body wanted more, more heat and touching and attention and a million other things. You ached for him to be inside you, a carnal desire that screamed to be sated by his lavish attentions.
It didn’t take very long for him to get the message. Kisses and touching became more fervent, his lips and hands exploring more and more of your body. Optimus had obviously done some research, somewhere, or perhaps Cybertronians simply had a similar-enough anatomy that there was little for him to find surprising.
Nevertheless, when he worked you open around one of his fingers, you couldn’t help but let out a soft sob of pleasure.
“ Optimus ,” you moaned. “ Please. ”
He was so gentle and so sweet, letting your cunt adjust to the size of the penetration before sliding in deeper. The fear for how you’d even take something larger than a finger was overshadowed by the growing pleasure that simmered in your core, made only worse with every glance you were able to spare to the autobot’s face.
His eyes were trained on you. Sharp orbs of winter-blue, curious and gentle, sought out any little reaction he could to understand how he was making you feel beneath him. He looked nearly awed by every little twitch, every moan, every plea that fell from your lips as he began to thrust that single, thick digit inside your body.
But it wasn’t enough.
You came close to climax a time or two, hovering just over the edge as you tried to figure out if your lover was doing it on purpose or not. Either way, your words found their mark when all you could sputter out was,
“Fuck me!” it was somewhere between a sob and a command. “Please, fuck me--put your sparkling in me, make me yours I need you Optimus--Ineedyouplease-”
The thrusting paused for a breath’s worth of time. You could almost feel him debating on asking a question, but felt it all the same when that question flickered from Optimus’ thoughts and he, finally, withdrew his hand from between your legs. The emptiness was aggravating. Your body was caught between carnal need and conscious thought, wanting nothing more than to be taken and smothered and loved all over.
So when you opened your eyes to meet Optimus’ gaze again, it was hot bliss to see him staring back at you. His face looked filled with the same kind of need that yours must have been--and with once glance downward, you could see exactly what he was, more or less literally, equipped with.
He must have saw your gaze, your shy expression, your body expression or something because Optimus suddenly took on, if only for a moment, that same awkward not-really-blushing look over his eyes and carefully pressed himself against your body. You could feel his heat, his strength, but you could most certainly feel the thick, pulsating warmth of his cock against your cunt. It practically hummed against your heat, leaving you eager and wanting all the same despite the size itself.
“I won’t do anything to hurt you,” Optimus murmured, pressing a kiss to your lips. “Do you still….?”
It barely took a second for you to come up with an answer; here he was, body over you and making you feel so delightfully small and powerless, a literal alien lover who was more than what you could have asked for with a cock ready to fuck you into next week and looked worried about hurting you?
“ Yes. ”
It wasn’t even a question that needed an answer to, yet you gave it anyways.
“Yes, yes yes yes oh please yes-”
You gave the answer with a breathless need, as if the world around you was going to crumble if Optimus didn’t fuck you now.
There was a single moment of silence, a moment that worried you immensely, that perhaps it wasn’t the right time, that he was having second thoughts, that maybe there was something wrong or-
And that's when you felt him shift, cock moving until the tip pressed to your entrance and he pressed himself inside of you. The motion wasn’t hard or forceful, but by god did you feel every little twitch.
You felt one of Optimus’ hands reach up to cup the side of your face against his massive, warm palm. It was a wordless comfort, one that you took greedily and nuzzled into--it kept you grounded as he slid deeper and deeper within your body, carefully opening you up inch by mind-numbing inch.
You’re not sure how long it took before he was settled within you, all you could focus on was the soft murmurings of comfort and encouragement from the bot above you, all the while feeling his hand against your cheek.
After a moment, you collect your thoughts and slowly nod your head, the answer to the unspoken question you knew was biting at his lips.
That’s all the answer that your lover needed.
Despite the immense difference of size between the two of you, Optimus was surprisingly precise with his movement. His thrusts were hard and quick, but not enough to hurt you. His hands were strong, but they didn’t grip hard enough that you feared for bruises. It was just heat and pleasure, all whirling around one another and clamoring over your thoughts as you tried to make sense of it all. You could feel him moving against you, feel the heat from his body, the piercing attention of his eyes.
The sound of his low, firm voice.
“You want me to sire a sparkling inside of you?”
It was less a question and more of a statement--one that you weren’t about to argue. Instead, the sound only made you moan louder, his name somewhere inside of it as he continued to press inside of you.
“You would--” Optimus’ voice sounded so delightfully strained, trying to keep himself composed enough to speak even while he was at the edge of pleasure-induced insanity. “-You would make such a beautiful carrier. Such a beautiful sparkling--I want--”
Your legs tightened around his waist as he quickened the pace, ramming hard and fast against your body. You could feel his cock rub against every good spot inside you, eager wetness leading down your inner thighs. There was a slick, wet noise every time Optimus moved--it only made the air feel hotter, your hands reaching for anything that you could grasp to keep you anchored down.
All the while, your lover continued to growl and purr sweet nothings into your ear.
“Do you like the way my spike feels inside of you? You’re so small and tight, you’ll look so beautiful and round when you carry our sparkling--I’ll make sure you’re safe.”
It was a wonder to hear the words coming from the leader of the autobots mouth, but it was a delight that you knew would be yours alone--a pleasure that nobody else had the right or the relationship to see from him. It only beckoned you further, closer to the edge, seeking out the pleasure that Optimus was so keen to give to you.
“Optimus,” you all but keened in delight. “I’m so close--socloseplease-”
You felt him rumble against you, the noise coming deep from his chest as he shifted to hold you close. His body was pressed to yours, just enough so that you felt smothered and small and beloved in more ways than one, his cock--spike--all the while hitting that glorious spot deep in your cunt that made you see stars in the back of your closed eyes.
You didn’t last more than a few seconds longer before you came, climax crashing into your thoughts like a red-hot wave. It poured through your limbs and swirled in your belly as you let out cry after fervent cry of joyful love and abandonment.
It was only a few moments after that you felt Optimus following behind, your body filling with warmth much differently than what his cock had felt like. You could feel him throb inside of you, hot and thick and perfect in more ways than you would have ever bothered to count.
You could distinctly feel yourself dripping with liquid, too much to take, and it dripped messily down your thighs from where you and Optimus were still joined.
All the while, every inch of existence felt like pleasure.
He held you until every ounce of climatic euphoria was gone, fucking you through it until both of you were exhausted and boneless and an absolute mess of body fluids.
When you finally had the mind to reach a hand down to press at your lower stomach, you did distinctly feel warmth, an extra curve to your stomach that hadn’t quite been there before.
“So,” you say at last, letting Optimus gently shift, turning your bodies so you could lay ontop of him. “If we’re trying for a sparkling now, I think that means we’ll be doing this a lot more often.”
And despite it being certainly impossible, you swore that you could see the autobot leader blush.