Warning: Explicit sticky based mech/mech interfacing ahead and mentions of mpreg in later chapters so you have been forewarned. Don't like? Then don't read.

Forgot to add with last chapter; thanks for all the story faves and reviews! Still a bit more to go.

Skyfire abruptly found himself lying sprawled on his back, legs pinned down. They'd already gone another wonderful round of interfacing with him on top, now Optimus had asserted his superior strength easily throwing the larger, much heavier shuttle onto his back, straddling his thighs and assuming the dominant position.

Optimus flashed him a broad lopsided grin, the scar inhibiting his ability to move the left side of his face. Blue hands deftly worked over the white mech's erect spike, tickling and teasing the sensor nets along the underside and toying with the tip. Watching them with curiosity as the smaller mech shifted back the shuttle nearly screamed when warm derma suddenly pressed to the tip of his spike before enveloping it and sucking hard.

Due to the disfigurement Optimus couldn't take any more of him into his mouth past the first ridge, but he put his derma, glossa and hands to work to make up for it. Skyfire writhed, bucked and moaned under the unrelenting assault.

Battle worn hands stoked up and down the white length with a firm grip occasionally slipping a finger or two down further to brush and tease over the slightly parted rim plates protecting his valve. The nicks and fine scars of the fingers and palm added to the friction as Optimus mouthed and scrapped his denta along the underside and prominent plate ridges of the hot length. He used his glossa and derma to play with and tease all the fine gaps and sensor laden plates along the spike, delighting in the soft moans and gasps he was wringing from the large shuttle.

Playfully flicking the pointed end of his glossa through the slit at the tip of the white mech's spike Optimus murmured, "Mmm you taste good." Licking up the leaking fluids he enveloped the tip again with his derma. A deep pleased hum rose from low in his throat when the shuttle shuddered hard, fingers clawing at the berth and small whimpering moan escaping the white mech's vocals.

Skyfire mind was reeling from the surprisingly skilled attentions. Oh Primus Optimus was good, so pit-damned good! Every touch of those rough hands, movement of that warm mouth and derma over his most sensitive equipment was driving him crazy. His pleasure shot processor barely comprehending anything outside the utterly wondrous heat suffusing through his frame.

All the euphoric sensations combined to drive the shuttle crazy! Spark swollen with built up energy beating franticly within its confines, the tell tale prickle of heat rapidly building within his pelvis. So close! He was almost at his peak when Optimus suddenly pulled away.

It took a few seconds for his lagging processor to notice the lack of attention to his spike. Looking up ready to protest he froze seeing Optimus up on his knees, thighs spread wide over the shuttle's broad hips. The truck-former's dripping valve hovered mere inches above the shuttle's throbbing spike. So close he could feel the radiating heat.

Any fleeting though Skyfire may have had that the truck-former might want to reverse roles this time - the shuttle being on the receiving end - were shot to pieces at the sight. He couldn't help the loud wonton moan that left him as he watched his spike being slowly swallowed into the taut, gripping heat. Optimus lowered himself carefully as the thick length spread and filled him. Tilting his hips changing the angle, Optimus' vents hitched as the spike pressed towards the back of his valve, stimulating a deeply recessed sensory nerve bundle just before the sealed plates at the end.

The red and blue mech held himself in place having taken as much of the white mech's length he could fit. In this new position it allowed the flyers impressive length to go that bit deeper, but still didn't allow the spike to be fully hilted making Optimus pause and consider his options.

Feeling the tip of his spike pressed rather hard into the end of ground mechs valve Skyfire expected them to stop there. Despite how utterly erotic it was to see Optimus posed so beautifully above him and taking him in that way he knew this wasn't going to work. The pressure on the tip of his spike was already becoming uncomfortable he could imagine the first proper thrust would end in a potentially painful disaster for both of them. Stroking his hands up their red flanks he opened his mouth ready to openly offer to take the truck-formers spike when he felt something change inside them. A loud gasp ripped from his vocals instead, optics growing wide as he felt the pliable plates at the back of Optimus' valve split and part.

Locking optics with the shuttle the truck-former gave one last sharp downward push, the remaining inches of exposed spike disappearing completely, hips connecting with a solid clank of metal. The friction combined with the sudden shock of Optimus' sensory nodes sparking off violently and sensation of his spike tip scrapping past the edges of the new internal opening finally tripped the white mech over the edge.

With a strangle howl Skyfire arched, body going stiff as the shock of overload crashed through his systems. Hands gripping at the white hips sitting atop his, he held them firmly in place as the pent up pressure in his spike released a heavy stream of transfluid deep into the others body. Optimus curled forward, optics flashing bright as long low groan issuing from his parted derma. "Ah! Oh, oh, Primus… yes, oh yes." The Prime hissed body trembling as dormant systems were stimulated into functioning again by the searing rush of the shuttles release.

Fighting for some coherency against the overwhelming pleasure from the post overload stupor his CPU had fallen into Skyfire drunkenly asked, "What-what did you just do?" Wiggling his hips driving a deep moan from them both Optimus lifted himself up a little.

"Something I almost forgot... ah, I had…" Staring at him in amazement something went off deep within the flyer's CPU. Mechs and femmes normally had no significant connected parts beyond the back of their valves aside from very small transfuild reservoirs at the back side of the valve and a connecter link to the spark. But this felt like he was breaching into an entirely new area within the mech, almost none of his release flowing back like one would normally expect, his processor whirred as it analyzed this extremely bizarre situation rapidly coming to one conclusion... he couldn't be, his conclusion had to be wrong, he just couldn't… could he?

"A-are you a bree-" His question died in his throat as Optimus rose up and slammed back down sending a mind blowing rush of pleasure through his frame from his over sensitized spike, spark swelling and beating rapidly within his chest in renewed arousal.

Beginning with slowly rocking his hips back and forth, gradually moving up to a full rise and fall pattern Optimus figured out his limits in this new position. Small soft moans slipped past parted grey derma as the red and blue mech worked towards finding his rhythm. The delicious variations in friction created with each slow rolling rise, adjustment and fall of his hips driving Optimus to hunch his shoulders, bracing his hands against the shuttles lower abdomen or loose his balance under the steadily increasing heady rush of pleasure and friction.

Large hands sliding up to hold a narrow waist, Skyfire helped steady and guide him as Optimus finally found his rhythm and set the pace. Internal walls rippled and squeezed his thick spike in varying patterns with each thrust in ways Skyfire had never known anyone could do. It felt like each ring of muscle cables was working independent of the others to maximize contact of all the sparking sensor nodes.

Skyfire found couldn't take his optics off of the delicious sight of Optimus undulating above him, back arching out and in with each roll of hips putting his well constructed body on display, slanted blue optics intently locked with his glowing bright.

The pace soon increased. The smaller mech using the powerful muscle cables and hydraulics in his legs and lower body to lift himself til their bodies were barely connected before allowing gravity to drive him all the way back down, hips fully meeting with solid metal on metal thunks. Rolling his hips upwards to meet each of their downward strokes, the shuttle drank in the wondrous deep grunts each impossibly deep penetration forced out of the beautiful mech.

Like always it seemed far too soon before both were reaching their peaks. Crying out Optimus' name Skyfire forced them down onto him one last time, holding the truck-former in place as overload ripped through him. Spark pulsing madly with release, transfluid burst from his spike in pulsing waves as bolts of charge shot between their joined plating.

The shock of a second load of searing hot fluids erupting so incredibly deep inside him drove Optimus to his own overload. Usually not overly vocal during overload he couldn't contain the loud scream of Skyfire's name as newly awakened systems were severely over stimulated. His internal muscle cables rippled and violently contracted around the thick length buried deep inside as a flow of soothing coolant took the edge of the burning heat created by their coupling.

Skyfire choked as his spike was so viciously squeezed the sudden mix of pleasure and blunt crushing pain drove him into a second, minor overload. What little remained of his transfluid forced out in a short spurt into the mech above him.

Unable to hold himself up, energy finally expended, Optimus barely managed to disengage himself from the shuttle before he collapsed on top of him. The room echoed with the sound of their combined vents cycling hard trying to suck cool air into their overheated, pleasantly sore frames.

Recharge tugged at the back of Optimus' CPU as he moved to settle more comfortably across the shuttle's frame. Skyfire gently stroked Optimus' broad red back savoring the slowly dissipating aftershocks from some of the strongest overloads he'd experienced.

"Um… Optimus?" Bleary blue optics flicked up to regard him. "I have enjoyed our short time together and… I can see this becoming something more… You're everything I could want a-and… I know you are the Prime. I understand your responsibilities to all our kind and will understand if this can't work but…" Skyfire struggled to word it just right, not wanting to ruin what they had started.

"I just want you to know I want you for you Optimus. I feel you're someone I can trust… who's always believed in me… you've never begrudged me my ill made decision to join the Decepticons for how short a time as it was. You accepted my pacifism and haven't once asked me to even consider raising a weapon against another… and I've found you're almost everything I could want in a mate. I know this is very forward of me but… Would… w-would you have me as your mate?"

Optimus' optics flared, face plates becoming drawn before he quickly tilted his helm down away from the shuttles wide, nervous optics. The seconds seemed like hours as the shuttle waited for the truck-former to respond, that old icy fear he had felt several hours ago beginning to prickle through his spark again. Maybe he'd read things wrong and the Prime didn't want anything more outside an interface partner.

Biting his lower lip Skyfire turned to his helm to face the wall, not wanting Optimus to see his fear and anxiety. A gentle brush of fingers along his cheek prompted the shuttle to hesitantly turn back to face Optimus, a barely noticeable smile pulling at his derma. "Hmm, I'd like that. I must admit I have enjoyed your presence here on the Ark and I am sorry for not making more time to get to know you better before now. I have been thinking these past hours and I find myself wanting to honestly rectify that... and our time tonight has been most enjoyable. This is somewhat embarrassing to admit, but it has been so long since I have felt so thoroughly sated and pleasantly exhausted that I honestly cannot clearly remember it." Skyfire ducked his helm in mild embarrassment at the compliment, slinging his arms around the smaller mech.

However the sweet little moment was broken as the light in Optimus optics turned steely. "But I must tell you that if I fully accept you things will change. There will be mechs out there seeking to drive you away from me, to harm you just for being with me and your peaceful, sweet nature will not protect you. I do like and admire that aspect of you and your strong convictions but those aspects will also make you a soft target. The Decepticons would not hesitate to try and take you or kill you in an attempt to demoralize and weaken me." The shuttle nodded, hugging the truck-former tightly into his frame. "I didn't mean to make that sound so harsh, but lying would only hurt you more. It is the blunt truth of how my life is and why I have not accepted a mate in so long. Can you accept that?"

"Yes, I understand… and I don't care. I've seen the war first hand. I appreciate the dangers and I've thought long and hard about this. I know there are mechs that won't like me being so close to you and I've come to accept not everyone will ever grow to like me… but I want you and nothing is going to deter me… that is if you will have me?" Optimus chuckled softly at the introverted mechs dogged determination.

"Hmm… then I accept. Know that despite my life being as hectic as it can be I will always here for you when you need me," Smiling he pressed a chased kiss to the shuttle's jaw adding with a sultry purr and a slow trail of fingers along his jaw and neck, "or want me."

Skyfire's spark buzzed hotly at blatant invitation, but exhaustion won over acting on it. Who knew the Prime could be so insatiable and such an awful tease. Certainly no one he'd spoken to about the mech.

Shifting to curl up atop the large mech tucking his helm under the shuttle's chin, mindful of his long audial spikes Optimus let the need for recharge start to take over. The odd feeling of safety in the other mech's large arms lulling him into a deeper state of recharge than his always over clocked processor would normally afford him.

Grinning like an idiot Skyfire continued stroking his new mate's back as he felt their body go limp in recharge. He truly had a mate! Optimus had accepted him as more than just an interface partner. The idea of proposing being mates to his tiny number of previous partners had crossed his mind while he had been with them, but he never felt so sure, so right in making the decision to ask like he had this time.

He would have gone out and danced in the sky to express his great excitement and happiness if he weren't so utterly contented and drained. Tightening his arms around his new mate in one last hug, Skyfire felt his systems start to drag him down, the memories of their time together still playing though his mind.

I have a mate, I really have a mate! That was his last, semi-coherent thought before the desperate need for recharge pulled him into its dark embrace.