(This is a rewrite of an old story I had here. Optimus was so badly written in the original, I couldn't stand it anymore and decided to get rid of it.)

Smut with my main smutty oc, Dawn, who has the power to control metal, loses her powers after sex and in this one suffers from a completely new problem.

So no great plot, just some fun. No need to think how they're the same size or anything like that. x)

I don't own Transformers.

Dawn stood behind the Autobots, arms tightly crossed and eyes cast down to the gray floor. Everyone was listening closely to Optimus as the Autobot leader talked about something important.

Dawn couldn't focus on a word he was saying.

The pressure within her was growing, gripping her insides and getting closer to insufferable levels. Unbeknownst to Optimus, his deep voice was making it worse, every resounding syllable causing Dawn's racing heart to jump almost painfully in its confinement.

It wasn't completely new. Her powers had been unstable for some time, growing in intensity until they spiraled out of control and burst out one way or another unless she got help with it or helped herself.

Meaning she needed sex.

Why that affected her powers, Dawn had no idea, but so far no one else knew about it, and that was the way she wanted to keep it. Unfortunately, the mistake she had made last night was now threatening to end that secrecy.

She had been chasing for the relief, as she had done many nights, her fingers not quite doing the trick this time. For whatever reason, her mind had turned to Optimus, picturing him doing things to her she knew the serious-minded Prime never would, and surprisingly it had driven her over the edge in no time.

The next morning she had emerged from her quarters well-rested and joyful, glimpsing with bashful reminiscence at Optimus' red-plated back and broad shoulders, only to have the wave of returning pressure nearly drop her to her knees.

That had been the start of her current suffering. The pressure had never escalated that fast, and not knowing what to do about it, she had decided to endure to the meeting's end, and make a break for her room as soon as it was over.

"Dawn, you're with me today."

She hadn't taken into account the possibility of Ratchet and a long list of urgent chores intercepting her.

The orange and white medic didn't wait for a reply, heading for his work station. Dawn clenched her teeth. The pressure had become incessant hot prickling beneath her skin, but she followed the diligent mech anyway, intending to finish the workload as quickly as possible.

It wasn't easy. Right away it became clear she needed to concentrate hard on not destroying the things she was trying to fix. It was giving her a headache, which in turn caused her to make mistakes that earned annoyed comments from the poignant medic. All of it only added to her anxiousness.

"Could you at least try to apply force evenly?" the scowling mech grumbled, sharp optics inches away from the small parts of a delicate instrument they were modifying on a workbench. "I don't need a Bulkhead number two here, thank you very much."

"Do it yourself then!" Dawn finally snapped, flinching as the device she was supposed to be gently reforming, crumbled into a useless lump of metal.

Ratchet stared down in shocked disbelief, as did Dawn. She felt horrified, realizing it could've as easily been the medic's hand or head. She waited for the 'I needed that' or some other earned scolding, but it never came. Instead, Ratchet held back his annoyance and looked at her with concern.

"What for Primus' sake is with you today? You've been dangerously careless with your powers."

"I-I'm sorry… Really... That wasn't supposed to happen."

"What do you mean? You're not in control of your powers?"

"No... it's not that", Dawn suddenly recognized the bad route they were heading for and hurried to give some explanation. "I just have a headache today. I can't focus."

That only made the Autobot medic frown. "I should give you a quick checkup."

"No!" Dawn refused sharply, practically sensing Ratchet's processors analyzing her. "Really, I'm fine. I just need to rest for a while."

Right away she felt another surge coming and turned to run away. "The sooner the better!"

Ratchet watched her go, displeased. It couldn't have been more obvious she was hiding something more than a simple ache. And secrets, especially health-related, were something he was absolutely not going to have on his watch.

Shaking his head and sighing, Ratchet opened a comm. link. Fortunately, he knew just the right mech to dig the necessary information out of the evasive human.

Dawn rushed through the hallway, heading for the safety of her room with both her head and heart pounding wildly. She had already lost control of her powers and she had to make sure it wouldn't happen near any of the Autobots again.

Just as she reached her door, a deep baritone startled her.

"Dawn? Is everything alright?"

It had to be Optimus, didn't it? Perfect. Just goddamn perfect.

Forcing a smile on her face, Dawn turned back towards the hallway and the catalyst to her current torment. "Yeah. Why?"

Blue optics watched her with concern from their towering height. The mere sight of the strong and compassionate Autobot leader was making Dawn feel dizzy.

"Ratchet informed me that you were having some problems."

Of course...

Dawn could barely keep her eyes on the tall red and blue mech. Even the careless smile became too much to maintain. "I already told him it's nothing. I just need to rest."

Optimus observed her calmly, continuing with a sympathetic tone. "Of course. Allow me to accompany you. I would like to hear how humans generally treat this kind of symptoms."

"No…" Dawn all but groaned, trying to think of something, anything, that would get the Autobot leader to leave. Her head was killing her. Why was it so difficult to get a moment of privacy?

Also, why did the hallway become blurry all of a sudden?

Dawn's legs gave in and she teetered, swiftly swept up before she could fall. She grasped for support in confusion, not having the faintest clue of what had just happened. Had she blacked out?

More importantly, was Optimus Prime holding her in his arms?

"Put me down!" she screamed, instantly feeling the vortex of her powers reacting to the close contact, trying to find a way out.

The Autobot leader's blue optics widened, alarmed by the fear in her voice. "What's wrong?"

"Just believe me!" Dawn pleaded, an image of Ratchet's crumbled up tool flashing in her mind. "You have to get away from me!"

She started squirming and pushing at the red-plated arms to get down, but Optimus tightened his hold to keep her still. "Dawn, you couldn't even stand a moment ago."

Dawn doubled her effort, still getting nowhere from the unyielding grip. Her powers were cooking up a massive storm inside her and she didn't dare to use them even a bit, certain she would end up hitting Optimus with it.

The large mech opened the door to her room and carried Dawn in, ignoring her furious flailing. "It is best you calm down. I will summon Ratchet."

Doing so wouldn't help! It would only make everything worse. Dawn's head and insides already felt like a furnace. She had to get Optimus to leave. Now.

"GET OUT!"

With a tormented screech, a wide gash tore into the metal wall as Dawn's powers responded to her unstable emotions. She stopped her struggling immediately, terrified by yet another violent event she hadn't intended to happen.

"Dawn...?" this time Optimus didn't stop her as she carefully renewed her effort to get down. "Why would you go to such lengths…?"

Dawn couldn't bear to look at the Autobot leader anymore. She staggered to her bed and slumped down on the edge, burying her face in her hands. "Go away."

Even without looking she knew Optimus was doing nothing of the sort, more likely trying to make sense of what was happening and why she would attack him like that.

"I am not your enemy", the deep baritone assured gently. "I only wish to know what is causing you such distress."

The brief release of her powers had given Dawn a small breather, which she knew wouldn't last long. "And I'm not yours, but if you don't leave now I will end up hurting you."

"I do not believe you will", heavy steps approached her slowly, followed by a creak of metal as Optimus knelt down in front of her.

Dawn squeezed her head tighter, sensing the Autobot's presence painfully easily. "I can't control my powers right now, and you're making it worse by being here."

"Dawn, you collapsed just now. If you know something about what is ailing you, you need to tell me everything. I will do anything I can to help, but right now I am not leaving your side."

Dawn shook her head in growing frustration. How about a quick fuck? Yeah, there was a sentence she'd definitely utter to the noble and serious-minded Prime.

She felt a touch on her hands, and before she could protest, they were gently, but firmly pulled away from her face. She made a feeble effort to free herself, again to no avail. The large Autobot held her hands easily enveloped within his, blue optics studying her in search of answers.

"Will you tell me something before I call Ratchet?"

"I… I can't…" Dawn didn't know where to look, but she sure as hell didn't want to keep looking at the alluring, brilliant optics. Her heart was on the verge of a severe tachycardia already.

"Haven't I earned your trust?"

The unfair accusation made Dawn push her fear aside and look at Optimus, though doing so only pained her more. "Of course you have, but this... is different..."

"How?"

"It just is! Will you please get out before something bad happens."

"No", the red and blue Autobot refused more adamantly. "Whatever it is that's affecting you, it is clearly serious. I am not leaving you alone while there remains a chance you might lose consciousness again."

"Optimus, please..." Dawn pleaded tiredly, almost ready to do anything just to stop the burning. "I don't want to hurt you."

"You will not. Just tell me how to help you."

Dawn said nothing. The earnest mech had no idea what he was offering.

"Then you leave me no choice but to call R–"

"No!"

Dawn felt herself crumble under the physical and mental strain. Humiliation was starting to rise above other feelings. "It's… it's not… I can do it myself… if you leave..."

"Do what?" Optimus kept pressing her for answers, noticing too that she was starting to give in.

Dawn bit her lip, knowing she wouldn't be able to stop her malfunctioning powers from erupting soon again. She hesitated for a long moment, before opening her mouth and clumsily searching for the right words.

"My powers… they don't stay the same anymore. They get stronger, building up this pressure over time until… that happens", she gestured towards the large hole in the wall with her head. "Unless… um…"

At that point her face grew red. She muttered the rest quickly.

"What?" Optimus sounded like he wasn't sure he had heard her correctly.

Dawn refused to look at the kneeling mech, keeping her face down while explaining with utmost reluctance how her powers worked. When she stopped, there was a painfully long silence. She didn't think it was possible to feel any more mortified.

"So, this is... a sensitive subject for you?"

"Yes, it is!" Dawn glanced up angrily before returning her eyes down to the large metal hands that still held hers. "Do you seriously think I could've just walked over to you and asked you to help me with something like this?"

There was only sincerity in the Prime's softly rumbling reply. "It is my understanding humans and Cybertronians share fairly similar anatomical structures, albeit the difference between our metal and your organic parts. So yes, I would've preferred for you to come straight to me with your problem."

Dawn's head jerked up. Was he serious?

Optimus had in turn lowered his gaze down to their hands, optic ridges hanging low in contemplation. A metal thumb brushed over Dawn's wrist, sending shivers through her already overworking nervous system. She couldn't stifle a pained whimper as the pressure began rising insufferably again, a barrage of hot nails stabbing at her insides.

The blue optics darted back to her eyes. There was no hiding her suffering from their piercing light.

"What will happen if you stay like this for too long?"

A new determination had settled in the Prime's gaze, a kind that unnerved Dawn without her being sure why. "I... I don't know. It has never gone this far. But –"

The Autobot leader released her hands and stood up, reducing the rest of Dawn's sentence into a surprised yelp by suddenly lifting her by the shoulders and pushing her back on the bed. She stared up wide-eyed and in utter disbelief at the large mech who had just straddled her much smaller body, large hands keeping her shoulders pressed against the sinking frame of the bed.

"W-w-what do you think you're doing?!" she stuttered, even though their new position left little room for misinterpretation.

Optimus met her surprised eyes with the same unnerving determination, discontentment evident on his stern face plates. "You have done very little to convince me you will be fine on your own. Since you are not willing to co-operate and your state appears to be deteriorating again, I am compelled to take matters into my own hands."

Dawn felt her powers tugging like a trapped beast inside her, ready to break out again any second. Fear overtook her, making her struggle against the heavy metal pinning her down.

"Why won't you listen! I can't control myself! If I hurt you –!"

The blue helmet-like head came down and captured her mouth in a weighty kiss.

Dawn's hands shot up against the windshield-covered chassis. She was shocked, barely breathing as the metal lips moved against hers. A tingling current seemed to flow through her, carrying away some of the pressure generated by her powers, while awakening another one in the lower portion of her body.

One restraining hand left her shoulder, reappearing down by her waist. Dawn tried to move away as she felt the large digits slide under her clothes and tug them down, managing merely muffled protests through the forceful kiss. Despite her efforts, the Autobot leader had soon stripped her lower body and positioned himself between her spread legs.

At that point Dawn slammed her fist against the broad chassis as hard as she could. Finally Optimus released her mouth, though the look in his glowing optics wasn't any less unyielding.

"I am sorry. I do not wish to cause you pain or distress, but in these circumstances I have to do what I can to protect you. Even if by doing so I will have to earn your hatred."

"Hatred?" Dawn repeated in disbelief, panting heavily from the physical and emotional stress. "I don't hate you. I couldn't hate you if I tried. For god's sake, the last time I was taking care of this problem I got off by thinking of you!"

Even as Dawn was spitting out the heated words, she could feel her face turning red. She kept her eyes defiantly on the silent Autobot nonetheless.

"I imagined us like this. Then this morning when I saw you again... the pressure started building again, much sooner than it should have."

Optimus didn't respond right away, his serious expression keeping whatever feelings he had a secret. "If you are open to the idea of the two of us interfacing, why are you fighting this?"

"Because..." the anger wore down from Dawn's voice. "… you don't feel the same way."

A heavy sigh sheared off some of the Autobot leader's edge. "There is more this war has taken from us besides our planet and countless friends. As long as it continues, there are things... bonds, I fear I am unable to commit to. Right now my responsibilities have to come first, in all matters."

Dawn knew that, but it didn't ease the annoyance she felt. A trickle of sweat ran down from her temple, and she swiped it away, noticing that her hand was trembling. She didn't have much time.

"That's fine, but I don't want such a one-sided experience and I certainly don't want to hear you say you're sorry about it. Just leave now and let me take care of it myself."

Optimus watched her silently, before closing his optics. When he opened them again, the burdened demeanor was gone, replaced by steely resolution. "If you find it discomforting, I will not apologize anymore. Other than that, I am giving you no choice in this matter. I can only promise I will try my best to make the experience pleasurable for you, despite the circumstances."

The amount of authority the age-old Prime suddenly hit her with was impossible to ward off. Fazed, Dawn didn't move as Optimus raised his hand from her shoulder, cupping the side of her head and fixing her with a firm gaze. "I can see you're hurting even as we speak. Seize your resisting. It will only make this harder for you."

This wasn't the Optimus Prime Dawn had always known. The stern metal features hovering over her held no trace of gentleness. This was the powerful, battle-hardened commander of the Autobots, who had set out to impose his considerable will on her, whether she liked it or not.

While Dawn was still digesting this jarring realization, Optimus brought his mouth down to the side of her neck. Dawn shuddered and squirmed from the ticklish feel, grasping the broad metal shoulders above her. The deliberate distraction didn't take her attention away from the bulky fingers she felt probing outside her unguarded entrance. Her breathing became frantic and her legs squeezed the Autobot leader's sides, trying to stop the intrusion from happening.

No! She wasn't ready! What was she supposed to –

"Do not fear", the deep voice rumbled close to her ear. "Focus on what you are feeling. The pain will ease soon."

Two of the metal fingers pushed in. Dawn found it impossible not to focus on what she was feeling. Her unprepared walls were stretched as far as the thick digits could go, making her squirm under the large Autobot's frame. Then they pulled back, allowing her to breathe for a second, and re-entered decisively. Again. And again.

Long enough for it to start feeling good.

Dawn couldn't even begin to try and deny the intoxicating pleasure that was accumulating from the continuous thrusts and the teasing kisses and bites on her neck. She was starting to feel hot and lightheaded for a different reason, gradually getting over the pain her malfunctioning powers had caused her. Despite the forceful way the Autobot leader had asserted himself, Dawn had to admit, she was enjoying their encounter.

The slick digits slid in and out with growing ease, rocking Dawn's lower body with every move and making her head swim with burning need. Wanton gasps and moans escaped her, unable to be held back anymore. Optimus placed his hand back on her shoulder to keep her still as he sped up his pumping.

The pleasant haze turned into a blinding cloud of sexual energy that erupted all around and within Dawn, making her writhe in the clasps of her release.

The large hand slowed its rhythm, but didn't stop. Slowly Dawn regained her senses enough to realize the threat was over. Her pressure problem was gone. For now.

"You can stop..." she tried to save the Prime from his unnecessary and possibly unpleasant effort. "The pain's gone..."

The fingers stopped their satisfying motion, lingering within her moist flesh. Dawn heard nothing from Optimus, save the steady whirring of some internal cooling system. She looked up from her pleasurable haze. The blue optics avoided her gaze. There was something off in the large mech's tense posture. Even the weight on Dawn's shoulder had grown uncomfortably heavy, as if Optimus had forgotten his hand was still there. Dawn focused on the Prime's face plates.

Was he annoyed?

"What's wrong?" she asked. She had never seen such an expression on the Autobot leader.

"Nothing", the deep voice was as distant as the brightly glowing optics. "I am fine."

Had his optics always been that bright?

"Really, what are you thinking? And before you make some lame excuse, I'll remind you that after my humiliating confession, the least you owe me is an honest answer."

Optimus couldn't have looked any more reluctant, but was apparently unable to refute her reasoning. He withdrew his fluid-coated fingers and placed his hand on the bed next to her. With an exasperated growl, he started.

"There is nothing wrong. Merely... some long dormant functions have been unintentionally activated again by our interaction."

It took Dawn a moment to catch the meaning of his words and when she did, she was too surprised to respond properly. "You're... aroused?"

The annoyance was now clearly visible on the Prime's face. "Yes, briefly put. The thought of stopping doesn't appeal to me anymore."

The red and blue mech's optics stole a glance at her naked form, before meeting her eyes. "I can feel my spike trying to pressurize as we speak."

Dawn's surprise must've shown, since the annoyance on Optimus' face plates made room for a dry smirk. "My apologies for the crudeness. It seems today I have done nothing but cause you a shock after another."

Dawn stared up at the large mech, trying to get her thoughts in order. "Why does that make you angry?"

Optimus shook his head sternly. "With the number of responsibilities on my shoulders, I cannot afford such lapses in self-control."

"You can this one."

Dawn's statement surprised herself more than it did Optimus. What blatant irony, when just a little while ago she had been ready to throw the Autobot out. But if he really did want her instead of simply doing what he felt was his duty…

Optimus didn't seem thrilled. "I have already forced you into this against your will, and now I should take my own pleasure from you?"

The low, dark tone only made Dawn's heart pound faster. "It's hardly your pleasure alone."

"You don't want me to leave anymore?"

"No. What about you? I thought you said you were unable to commit to such bonds."

"That was my belief. Now I am… not certain anymore."

Dawn had heard enough. She wanted more and she knew so did Optimus. "Do you want to leave?"

"… No."

"Then seize your resisting and show me how you bots interface on Cybertron."

The prominent metal brows raised dubiously as Optimus heard her straightforward provoking. "Are you certain?"

Dawn pushed herself up on her elbow, reaching for the large hand that had just driven her over the edge. Without hesitation, she pulled it to her face and took one of the black metal fingers into her mouth.

"Mm-hmm", she gave a confirming nod while her tongue played with the thick finger.

The bright lights in Optimus' optics grew noticeably for a second. Still, hesitance returned to the metal features, a battle between what looked like impatience and yearning.

"You might come to harm."

"Mm", Dawn let the finger out of her mouth, planting a soft kiss on the tip and casting the large mech an unabashed look. "Oh? Are you that big? You know that's only making me more curious."

The faint internal whirring Dawn had noted before kicked into a higher gear, as if the Autobot leader had been holding back for too long. "If that is indeed your wish..."

Releasing her shoulder from the heavy grip, Optimus sat back and brought his hand down to his crotch plating. "Allow me to first complete a systems check to see everything is... in working order."

Dawn's eyebrows raised up and she couldn't help but give a mischievous smirk. "You haven't gotten rusty, have you?"

Optimus glanced up quickly, looking downright appalled at the suggestion. Then he caught on to her joking and returned to his task with a low muttering. "I certainly hope not."

There was a faint sound of metal plates shifting. A look of triumph crossed the Autobot leader's features. Dawn couldn't help but smile at the unintentionally charming expression, the careless amusement wiped from her face as soon as she laid her eyes down to the length that was swelling up in front of her astonished eyes.

Holy hell, the Prime really was big.

Optimus leaned back down over her, actually giving an uncharacteristically smug smile before catching her mouth in a gentler, more seducing kiss than before. Dawn participated eagerly, running her fingers on the cables lining the Autobot's neck. The metal under her touch radiated with excess heat.

Optimus dug his hand between her and the bed, correcting his position so he could bring the tip of his spike to her entrance. Dawn was now faced with the Autobot leader's chassis, seeing little else. Her breathing quickened in nervous anticipation as she felt the hard appendage prod between her slick lips.

"About your suspicions concerning my alleged 'rustiness'..." the deep voice vibrated through the truck-like frame. "I would like to present my counterargument."

A firm thrust made the waiting spike plunge into her aroused heat.

"Ohhh...!" Dawn gasped, every ounce of her focus fixating on the hot, pulsating girth that suddenly filled her. "Wow..."

"I thought as much."

The hand beneath her lifted her and pulled her further onto the erect spike, hindering Dawn's thoughts and awakening an instinctual fear in her as she was taken to her limits. The stress on her body was overwhelming, and she was almost ready to beg the large Autobot to stop.

Before she could, the forceful motion stopped on its own. The hand supporting her rubbed her hip soothingly. Dawn looked up, seeing the brilliant optics shine the whitest of blue she had ever seen, while still watching her with every bit of the Autobot leader's caring spark in their blaze. It comforted her immediately.

"I didn't know you could be this... intense", she smiled shakily.

"I wasn't sure myself if I could find the spark for this", Optimus confessed. "After everything the war has done to us. Now... I find myself wanting this almost too much."

The large mech rolled his hips, making Dawn see stars for a moment. She knew what he had meant. There was impatience the Prime usually never displayed.

"I am sorry... if I am causing you pain", the red and blue Autobot growled, lowering his head next to Dawn's and pressing it into his tensely balled fist.

Sorry or not, he wasn't stopping. The next heavy jerk of his hips buried the sizeable spike so far inside Dawn, it made her back arch and toes curl. Optimus wrapped his lower arm further behind her, squeezing her body tighter as he repeated the mind-blowing thrust that soon settled into a rhythm of vigorous ramming.

For a while there was no distinction in Dawn's mind between the two of them and their differing physiques. She twisted her arm back to grasp the side of the blue helm and locked her legs tighter around the bucking metal hips, focusing with every fiber in her pleasure consumed being to bringing them closer together.

Optimus continued pounding his spike into her with his powerful mechanical frame. Nonsensical words tore out of Dawn as she felt the peak coming again.

"O-Optimus...", she breathed an urgent moan just as the pleasure exploded within her, rising to impossible heights with every heavy thrust that followed.

When they stopped, Dawn was left gasping for air and staring up at the metal chassis. She could see her own shadowy reflection in the windshields. She let her muscles loose their built-up tension and took a deep breath to steady her breathing. The thick spike was still lodged inside her, forcing out the excess fluids that slowly oozed out of her. The bulky metal fingers were digging painfully into her backside, but she didn't care.

The Autobot leader pushed himself up on one arm, looking down at her with concern, but also a kind of relief.

"Are you alright?"

Dawn nodded. "Better than my bed. I think I heard it crack at some point."

"My apologies if that is the case."

"You still apologize too much."

"I will try to improve on that."

Dawn smiled, content, but not sure what to say next. She was relishing the feel of the Autobot leader filling her, but at the same time expecting him to leave right away. "What now...?"

The blue optics had returned to their normal glow, their contemplating look catching a hint of hesitance. "What would you prefer?"

"Are you asking because you want to stay, but feel guilty for leaving your duties to others for a while?"

"That... is a possibility."

Dawn grinned, reaching for the metal chassis to get the large mech to come back down. "Then I would prefer for you to keep me company for a little longer. You know, to make sure my power issues are completely taken care of."

Optimus answered her with a conspiratorial smirk Dawn could've sworn was the sexiest thing she had ever seen. "I did promise to help you any way I can."

"Was that a one time offer or –" Dawn started, never getting to finish the sentence as the Prime suddenly pulled her up with him, her full weight coming to rest on the eagerly twitching spike and introducing her to a completely different kind of pressure.