Title: Momentum
Pairing: FrostIron
Rating: M for sex and language
Summary: Loki appears in Tony's room one night and starts a chain of events that may or may not mean Tony falls for the one person he probably isn't meant to.
This chapter: The first time it happened, the Avengers had just returned from battle and Tony was exhausted.
Notes: This is my first frostiron (I will go down with this ship) and my first sex scene, so I hope it's okay! Also unbeta'd. I'm open to reviews and suggestions!

The first time it happened, the Avengers had just returned from battle and Tony was exhausted. Running on the remaining adrenaline alone, he'd headed upstairs to the relative peace of his room, to have a drink and crawl into bed, as he so often did after a particularly gruelling fight.

However, what he didn't expect to find is Loki waiting for him, still clad in his leather armour, although that damn helmet is nowhere in sight. Before Tony can protest or even ask what he is doing there, Loki pounces -locking their lips in a furious kiss. Tony's mind is going haywire, running every possible scenario in which this could happen, and even asking himself if he'd missed something. As Loki works his tongue inside Tony's mouth, he finds that he doesn't actually care what was going on and he decides to enjoy it while he can.

Returning the kiss as best as he can, fighting Loki for dominance, he flinches as his back hits the wall and he has enough presence of mind to lock the door before they find themselves in a rather embarrassing predicament. Tony pulls away from the demanding lips just long enough to tangle his fingers in that soft, raven hair and tug, hard. Loki groans, low in his throat, as Tony attacks the pale skin of his throat with lips and teeth and none of that finesse he was renowned for in bed. But dammit Loki had appeared with no warning and he tastes cold like ice and if he enjoys the downright sinful noises that escape from the god -well, no one needs to know.

Loki growls, planting his hands on Tony's shoulders, shoving, and as Tony's head hits the wall with a dull thud, Loki reclaims the shorter man's lips in a kiss that is all teeth and underlying anger that is almost fading into the lust that Tony had felt ever since that day in the tower -ever since those impossibly long fingers had wrapped around his neck and hurled him through the window.

Tony's hands scramble across the armour-clad expanse of Loki's chest -desperately seeking for a zip, a clasp, anything to feel bare skin underneath calloused fingers. He feels Loki smirk against his lips, before sensing a vague gesture being made and suddenly both of their clothes are gone and wonderfully cool skin is exposed to Tony's wandering hands.

Pulling away from the kiss -after all, air is somewhat of a necessity- Tony pushes Loki back until he falls onto the grey silk sheets of Tony's bed. He scrambles backwards, giving Tony room to straddle his hips and hover above the other man. Pausing, Tony admires the god laid out underneath him -the expanse of pale skin wrapped around a subtly muscular frame and the fan of the dark eyelashes over the angular jut of his cheekbones and the way his hair spread out on the pillow like a dark halo. Tony just has to laugh at the irony of that, but the chuckle catches in his throat as Loki's eyes snap open -green pinning brown with a look that contains an unidentifiable spark and a deep, gnawing hunger that makes Tony nervous at the same time as turning him on even more.

A shiver runs down his spine when kiss-swollen lips tell Tony, 'When you are quite done staring at me, Stark, I'd rather like you to fuck me.' The hoarse, lust-ravaged voice combined with explicit statement and the way that accent curls around 'fuck' has Tony nodding and reaching over to dig in a bedside drawer for the bottle of lube.

Throwing it onto the bed beside Loki, Tony reaches down to join their lips again, briefly, and then begins a path across his jaw and down his neck, along his collar bone and down, stopping to suck on one nipple, while playing with the other one with calloused fingers, savouring the noises Loki makes as Tony gently bites down before soothing the area with his tongue. Tony carries on his journey downward, sucking marks into intolerably pale skin that just begs to be marred with bruises and the kind of possessive marks Tony likes to make. Tony marvels at the way that biting down, hard, on Loki's inner thigh makes the god arch his back in a desperate attempt to gain friction on his aching cock. Tony grabs the lube and covers his fingers, tracing the vein up Loki's cock with his tongue as he slips the first finger inside.

Loki is almost whimpering now, and he looks so incredibly vulnerable that Tony couldn't help but stop and wonder why this is happening -why Loki randomly appeared in his room, what path led him here. Then Loki looks at him and makes an impatient noise and Tony focuses on the task at hand again, adding a second finger and thrusting them, opening Loki's body. A third finger slips easily inside and Loki is moaning now, a near silent litany of 'fuck' and 'Stark' and Tony is starting to feel overwhelmed. Removing his fingers, he covers his own length with lube, hissing at the contact on his impossibly hard and until now abandoned cock.

Tony settles between Loki's legs, hitching one up and onto his shoulder as Loki wraps the other one around his waist and pushes himself up, opening up for Tony, and watching the god below him so eager is incredibly hot to Tony and he pauses, mesmerised, before pushing in slowly. He doesn't doubt that Loki could take it quickly, but Tony wants to savour the moment, the image of his cock slowly entering this exceptionally powerful god and when he is fully seated, he leans forward to whisper into Loki's ear.

'How do you want it? Tell me.' After all, Tony figures, Loki is the one that came to him, so in theory he probably needs something. Loki whimpers again, at a volume that normally would be impossible to hear, but here, in the heavy silence between them, it fills Tony's ears and adds to the heat that is already pooling at the base of his spine.

'I need you to shut up and get on with it -although hard would be preferable.' There are still echoes of the usual demanding Loki that Tony and his team have to fight, but there is something there, underneath the words, that Tony can't quite identify, but he can relate to. He lets his head fall onto Loki's shoulder, and with a muttered 'fuck', he starts moving, gripping onto Loki's hips hard enough to bruise. Loki wraps one hand around the metalwork of the headboard, the other coming to rest on Tony's shoulder, digging his nails in hard enough to draw blood.

The noise of skin on skin is permeated with hitched breathing, gasps and muttered curses. Tony feels the heat building and building. Knowing he won't last much longer, he wraps one hand around Loki's cock, jerking him off fast and rough. He leans down, kissing Loki thoroughly, wondering at the taste of ice and magic and life that is so utterly Loki before the god is coming, back arching up in a perfect curve that has his chest rubbing against Tony as come splashes onto their stomachs. It doesn't take long for Tony to follow him over the edge, Loki's insides clenching around him as he thrusts through his orgasm.

Tony's arm is shaking, fighting to support his weight as he pulls out and collapses onto the bed next to Loki, thoroughly sated and completely exhausted -any adrenaline from the fight having worn off. Tony turns his head just slightly to look at the man lying next to him, eyes closed and breathing heavily.

'Can I ask what that was about?'

Loki rolls his head to the side, opening his eyes to look at Tony. 'No.' He answers stretching in a strikingly feline manner, wincing as he sits up. Before Tony can say another word, he's gone.

'Not even a thank you.' Tony murmurs. He calls for Jarvis to turn the lights off, and rolls over, curling up in the heat Loki left behind and falling asleep faster than he can remember ever having done so before.

When Tony wakes up the next morning, it takes him a while to remember that he'd had a god in his bed the night before. He asks Jarvis if it really happened, and he simply receives a sarcastic affirmative. Tony crawls out of bed, pours himself a scotch, and returns, sitting cross legged under the sheets as he considers the night before.

It'd been Loki that the team had been fighting, before he'd disappeared and assuming they'd won, the team had returned to the house and Tony had been accosted by Loki. He desperately tries to recall every detail, every little thing that may have given him some idea of why Loki had appeared like that. The only thing that Tony can think of, however, is the fact that he distinctly remembers Loki saying 'I need you to get on with it'. Not 'I want', 'I need'. The problem is that Tony is nowhere near a psychologist, and he has no idea what that would mean.

Although he does realise that it probably doesn't mean anything good.

Tony thinks all day. He sits through the debriefing, not listening as usual and nodding or shrugging in the right places. He sits through a movie with Steve, and he sits and watches Natasha and Clint train. Soon enough, though, the team realises that there is something wrong -Tony has never gone so long without insulting one of them. So they do the only thing they can think of -they call Pepper.

After the break up, Pepper had pretty happily settled back into being Tony's assistant and generally being in charge of, well, everything. She was an extremely busy woman, and the team knew that the only time they could call her was in the event of an emergency. So when she was called, she always came pretty damn quickly.

Upon arriving at the mansion that all the Avengers shared, she is accosted by different theories from four different, seemingly worried friends of Tony's, and Clint. Clint's theories tend to range from 'maybe aliens messed with his brain' to 'he just needs to get laid' so Pepper writes off everything he has to say. Pepper is somewhat of a mother figure to the Avengers, so she is the only one who, with a wave of her hand, can get them to shut up and disappear.

'Tony?' She calls as she enters the workshop, deciding that treating Tony like a scared animal is probably the best route to take.

'What does it mean if someone says 'need' instead of 'want'?' He asks, spinning around in his chair to face her.

'Well, it generally means that they need it, instead of just wanting it,' she answers, giggling at Tony's completely unimpressed look. 'I'd need context before I could give you a straight answer.'

'And I can't give you that context. But I still need an answer,' Tony says, more to himself than to Pepper. 'Right, this is completely hypothetical, okay? So, if someone tells you that they need you, when they could have just said they wanted you -is there something there to read into? Or could it just be a slip of the tongue?'

'In my experience, if we're talking about people needing each other, then whether or not it was a slip of the tongue, it'd still be the truth. You can say you want somebody and either not mean it or be covering up for the fact that you need them, but it tends to be harder to say you need someone and not mean it. Why are we talking about this Tony? What happened?' She asks, gently.

'Nothing!' He exclaims, far too eagerly, before flashing one of his patented 1000-watt grins and spinning back to his computer screen. Pepper is about to push him further when her phone rings, and she is demanded back at the office to check over things. On her way out, she explains that it's nothing but Tony thinking too much and he'll be back to normal in a couple of days.