This is the 'dirty' version of 'Alternate Always - Chapter 3.' Same content, just with all the smutty parts included. You'll need to read the first two T-rated chapters and if 'M' is your thing, skip over the third and read this instead.

Disclaimer: The only thing I own is my dirty mind and my filthy mouth.

He loves looking at her, and in this moment she's all dishevelled, flushed and kiss-swollen and his desire ramps up to an entirely new level. God, I've never wanted a woman as badly as I want her. Please don't let me embarrass myself. And then he whisks her shirt over her head in a move so fast it makes Kate's head spin.

Chapter 3 - The 'Mature' Version

Kate watches Castle's already lust-darkened eyes deepen to an inky blue; the look he's giving her is positively predatory, and suddenly she knows what all those seemingly corny lines in chic-lit are talking about, because her pulse quickens, her breath hitches, her chest heaves, her knees tremble and holy crap, there's a rush of heat and moisture directly to her core. Ha, I'm a romance novel cliché and it's a writer who's got me in this state. Gotta be some kind of twisted irony there.

She snaps out of her ridiculous musing to let her eyes wander over him; he's as dishevelled as she is, possibly a tiny bit unhinged and disbelieving, but definitely aroused, the evidence of which she could feel earlier and can now see clearly outlined at the front of his jeans. She tears her eyes away from his groin, with just the slightest twinge of feminine pride, and back to his face where his wickedly salacious look almost makes her combust.

A million thoughts are running through Castle's mind as his eyes drift over the heart-stopping sight before him; Kate Beckett is in my living room, in skinny jeans and a purple lace bra, breathless from kissing me, smiling and maybe trembling just a little bit. Whatever planets have aligned to make this possible, thankyou, thankyou. But when his eyes reach her newly exposed chest, there's a sudden, sharp intake of breath and his eyes immediately fly back to Kate's. She watches as his memory takes him back almost a year and she has a brief flashback too, as she unconsciously touches the small round scar between her breasts.

"Kate," he whispers, an obvious tremor in his voice and sudden, overwhelming sadness in his eyes.

"Don't Castle. Don't let the memory of that day spoil this," she implores. "It's okay. I'm okay." And as much to bolster herself as to calm and reassure him, she takes his hand and presses it between her breasts, over the scar and leans in to kiss him.

It's a gentle chaste kiss, almost comforting, and Castle feels a surge of emotions; immense gratitude that she survived, awe at her strength and a fierce, overwhelming protectiveness. A potent mix when combined with their undeniable and slightly overwhelming state of arousal and when she pulls back from him, smiling widely and taking his other hand, he feels a flutter in his chest and belly that can only be described as girly. He entwines their fingers, gently tugging her towards his bedroom, and the look she gives him; dark, unwavering, overflowing with desire, elicits a physical reaction in him that is anything but girly.

Deep breaths Rick. Get your libido and your anxiety in check. Christ, why am I so nervous? Because it's Beckett you idiot, because you're in love with her, because she's been the subject of every one of your fantasies, all of your dirtiest thoughts for the last few years and you wanna make this good... blow her mind, make the earth move, make her see fireworks. Hmmm, maybe I should have a run at writing romance novels or maybe Mommy Porn... Fifty Shades of Castle, because right there is every clichéd orgasm euphemism ever written. Ugghh. Calm the fuck down and focus and it'll be perfect. You're good at this Rick; you'll be good at it together. Yeah, providing I don't blow my stack the minute I touch her. God, enough with the euphemisms.

Deep breath Kate. God I want him, so why am I so nervous? Because it's Castle and because four years worth of fantasies and anticipation is a hell-of-a-lot to live up to. Just relax, everything about the two of us is a perfect fit, why would sex be any different? We'll be really good at this, won't we? Only one way to find out. Fuck, we're really going to do this and if he's really it, really my 'one and done,' then this is going to be the last time I have a first time with somebody. Yeah Kate, let your mind go there; that's really gonna help take the pressure off.

They are both lost in their own thoughts as they walk hand in hand across the living room, and surprisingly, their trembling tightly laced fingers is the only physical contact they make as they pass through his office. There's no frantic undressing, no trail of discarded clothing like a dirty version of Hansel and Gretel and no bumping into or climbing onto large items of furniture as they step into the private space of his bedroom. But there'll be no regret or disappointment at their apparent lack of desperation, because the way they are looking at each other, the way they touch each other in the lamplight beside his bed is breathtaking; tender, hungry, reverent and yeah, maybe just a tiny bit desperate, and it's perfect.

Castle lifts their entwined fingers to his lips and kisses hers softly before tangling the fingers of both his hands in her hair, pulling her towards him and kissing her; no teasing, no pretence, just the warm sure pressure of his lips and the bold stroke of his tongue. She opens to him immediately, releasing a small satisfied sigh, and then she sets to work on his clothes because he's wearing more than she is and they are both wearing far too much.

She grabs the back of his T-shirt and when he releases her mouth to begin trailing wet kisses down the side of her neck, she takes advantage of the temporary loss of contact and drags the garment over his head. Her hands immediately come to rest against his bare chest because she's desperate to touch him and she savours the feel of solid muscle beneath her fingertips as she contemplates divesting him of his pants.

He lowers his head then, places soft random kisses across her chest while gently stroking the underside of her breast and he smiles against her heated skin when he feels her take a shuddering inhalation. Oh he's got his mouth on my chest and is that... yep, he's got his thumb under my bra. Kate retaliates by swiping the pads of her thumbs firmly over his nipples, just once, and it's her turn to smile when it elicits the tiniest gasp of surprise from him. She's still grinning when she feels him raise his head and they take each other in, eyes eagerly roaming over bare skin in the warm yellow glow of the room and when their gazes drift together she follows his eyes back to her scar, watching as he tentatively touches the pink puckered area. He strokes a single fingertip over the risen but surprisingly smooth blemish, marvelling at how something so neat, so tiny, could be responsible for the absolute devastation it unleashed.

Neither of them wants to dwell on any part of that day but Castle can't and won't ignore the permanent reminders she sees every time she looks in the mirror and presses his lips to the bullet wound as he gently grazes his palm along the faded scar on the side of her ribs, from the surgery that saved her life.

Kate feels the surprising sting of tears as she watches him, and blames them on his infinite tenderness and his determination to not ignore what is now part of her. So when he returns his gaze to hers she smiles, because she doesn't want him to freak out about the fact that she's about to cry. Apparently her smile is sufficiently reassuring because once he sees it, he grins back and immediately reaches behind her and unfastens her bra with a practiced flick if his wrist.

"I'm so not thinking about how you got so good at that move," Kate chuckles, but all conversation is briefly forgotten when he swiftly dispenses with the flimsy garment and sucks one nipple into his mouth, swirling it into a wet, aroused peak.

"Not the only trick I've got up my sleeve," he teases before laving the same attention on its twin.

Kate drags his face back to hers when the feel of his mouth on her breast becomes too much, and kisses him hard as she drops her hands to grab his belt.

"What's up your sleeve isn't really what I'm thinking about right now, but that's good to know."

Castle does a double take then, and Kate grins wickedly as she watches him swallow hard, eyes widening. "God Kate, you're gonna kill me."

"Jeez, I hope not," she jokes, but then she tugs a little aggressively on his belt and her voice lowers a full octave when she says, "I've got big plans for you."

Yep, she's definitely trying to kill me.

Once Kate has his belt unbuckled she can't help herself. She wants to touch him, all of him, and her fingers drift immediately to his zipper. Both their pulses are racing at a frantic pace now and their breathing is rapid and shallow. Castle squeezes his eyes closed at the feel of her fingers sliding his zipper down and he does some lip biting of his own when those fingers brush over the length of him. Before he can stop her, not that he really wants to stop her but he's operating on a hair-trigger right now, she's pushing his jeans down his thighs; but when she bends down to push them lower, he definitely needs to stop her because there's no way he's letting her head anywhere near waist level. If her face ends up anywhere near my... or if she kneels down in front of me, that hair-trigger... gone!

As he drags her upright he steps out of his jeans and kisses her, a slow languid exploration of her mouth in an attempt to slow things down. She kisses him back, matching his tempo and it's deep and intense and wow, they really are good at kissing, but it's not enough.

They both begin an eager exploration of all those places they've never seen, let alone touched. Castle's hands drift back to her breasts, her belly, her hips and he commits to memory the subtleties of how and where she likes to be touched, what touches elicit those soft sounds of pleasure that make his heart race and other parts of him twitch, and he devilishly memorizes her ticklish spots because they might come in handy one day. Kate explores the broad expanse of his back, running her fingernails down his spine, feeling every dip and hollow, before teasing his chest with her hands and her mouth, loving the feel and taste of him.

She focuses her attention on his abs next, more defined than she expected and definitely her weakness. A six-pack, or even the hint of one has always done it for her and the feel of his muscles rippling under her touch furiously fans the smouldering embers if her desire; but when she slips her fingertips inside the waistband of his boxer briefs and they make contact the smooth hard length of him straining against the fabric, she thinks she might actually ignite. God, that's impressive is her final thought before he distracts her by flicking open the button of her own jeans.

"I'm feeling at a distinct disadvantage," he whispers, his breath hot against her ear. "You're still half dressed."

"So, do something about it Writerboy," she challenges huskily as she tilts her head to the side, allowing him access to the sensitive area behind her ear, which he is torturing with his tongue.

Not needing to be asked twice, he slides her zipper down, brushing his fingers over the lacy edges of her panties, but her jeans are too tight to allow him access to where they both crave his touch.

"Jeez, Kate. Did you pour yourself into these things?" he mumbles as he tugs in vain at the denim.

"Well, they weren't this tight before you fed me that huge plate of Cannelloni."

"Note to self. Next time, don't feed Beckett immediately before trying to get her naked."

"Shut up, and hurry up, Castle. Or there might not be a first time, let alone a next time."

He chuckles softly but his amusement soon morphs into a frustrated curse when the stubborn garment gets the better of his fumbling, eager fingers. When Kate swats his hands away, he lets her; steps back and watches her wiggle and shimmy out of the ridiculously tight jeans and if it wasn't one of the sexiest things he's ever seen, it would have been hilarious.

"God you're beautiful," he whispers, looking at her standing in front of him in just her purple lace-trimmed panties and his eyes devour her flushed, almost flawless skin and the soft, delicate curves of her body; but when her passion-filled eyes bore into his, his gaze becomes unfocused and he's a goner. He loses all ability to move, think or speak.

There's a scorching intensity in the rush of heat that perfuses every capillary when he eventually pulls her to him. The way her bare stomach and thighs are pressed against his unleashes a moan deep in his chest, a rough primal sound that sends a surge of heat directly to Kate's core.

Their hands are purposeful now, no longer randomly exploring and Castle sneaks his hand under the last of her remaining clothing. Kate gasps as his fingers slip into her rapidly dampening underwear and she thinks her heart actually stops briefly as he strokes her. She has dreamed about this, fantasised about it, his hands on her, touching her in the most intimate of ways and the reality of the connection, the intensity of his touch is overwhelming on more than a physical level. When his thumb begins slowly circling her clit, he slides a finger in and she whimpers, biting the curve where his neck meets his shoulder.

Castle doesn't even flinch at the ferocious pressure of her teeth because right now the world could end and he wouldn't notice or even care; Kate Beckett is whimpering and quivering under his touch and it's amazing and he just wants to tumble onto his bed and worship every glorious inch of her. God, she feels amazing, he thinks as he reluctantly halts the motion of his fingers to remove the final tiny scrap of her clothing. He kisses her deeply as he feathers his damp fingers across her belly and hips, dragging his thumbs in circles over her jutting hip bones before tugging her underwear down, and he smiles against her lips when she quakes just a little.

He walks them backwards until the backs of his knees make contact with the bed and he is about to sit down when Kate's hands fly to his hips and catch the waistband of his boxers. She is kissing her way to the hollow at the base of his throat when her palm makes contact with the smooth length of his arousal and he hisses loudly. Her fingers curl around him, stroke him and both their eyes drift closed at the sensation.

Castle is caught somewhere between needing to stop her before she ends him and wanting to thrust his hips towards her and beg her to never stop, while Kate's mind drifts to the numerous rumours about his size, and she can't help the smug grin that briefly graces her lips as she touches him. Well ladies, I can absolutely confirm that the rumours are one hundred percent true. White whale, indeed.

She manages to divest him of his boxers without breaking her rhythm but when she swipes her thumb over the moisture beading at his tip he has to stop her, takes her hand and tugs her down with him so they both finally land on his heavenly thousand thread count sheets.

A soft giggle erupts from Kate as they land less than elegantly and it's probably one of the most un-Beckett-like sounds he's ever heard; and he wants to hear it again and again. They are a tangle of limbs, her half on top of him and he takes her face in his hands. She's still laughing when their eyes meet.

"I love hearing you laugh," he says as he twirls a strand of her hair around his finger, his face more serious than he means it to be because there hasn't been a lot of laughter between then recently. When he notices the smile on Kate's face start to falter he lightens the mood, "Except of course, if you're laughing at me."

She grins at him, touches his lips with her fingers and then follows with her own lips, kissing him softly before whispering against the corner of his mouth, "Well, don't do or say anything ridiculous, and I won't have to laugh at you."

"So now would be a good time to shut up?"

"Think you can keep your mouth shut, Castle?"

"Can't guarantee I'll keep it closed, but I'm positive I can find alternate uses for it, other than talking." And with that he rolls her onto her back and crashes his mouth to hers in a long and heated kiss, made more passionate by the proximity of their now naked bodies. Pressed together in all the right places, they are both acutely aware of just how aroused the other one is and they both take a deep, shuddering breath to temper themselves and slow things down.

"I don't want to rush this," Castle tells her as he teases her earlobe with his tongue and lightly runs the back of his fingers from below her armpit to the crest of her hip, deliberately grazing the edge of her breast in the process.

"Me either, but keep doing stuff like that and I'm pretty sure you'll break my resolve."

"So I probably shouldn't do this then…"

She gasps loudly as he closes his mouth over one nipple, sucking it and the flesh underneath into his mouth and swirling his tongue in slow, firm circles.

"No, that's okay. You can keep doing that," she squeaks. Yeah, keep doing exactly what you're doing, and when you're done on that side, fell free to… yep, he's a mind reader… swap to the other side.

Eventually, he kisses his way from her breasts, down her torso and across the taut, quivering plane of her stomach, his teeth nipping at her hip bones as one of his hands gently stokes the inside of her thigh. His fingertips are nowhere near where she wants then, needs them, but they are close enough to have her nerve endings on high alert and her anticipation levels rocketing off the chart.

When his tongue traces the faint mark the elastic of her panties has left on the skin of her abdomen, she can feel his breath on her, feel the stubble on his chin brushing against her hypersensitive flesh, and she wants him to touch her; wants him to press his fingers inside her again, and move his tongue lower because she's absolutely certain that his tongue is going to do things to her that... Oh God, here we go.

Castle splays one large hand on her belly and lowers his mouth to her, stroking his tongue firmly over her hot, aching centre. She tilts her hips upwards, she can't help it, and if her eyes were open, she'd see a brief grin play across his lips before they descend on her again.

Castle breathes in the scent of her - musky arousal and Kate; a heady combination, and the taste of her, God he just can't get enough. He also revels in the way she responds to the warm suction of his lips, the friction of his tongue, the welcome invasion of one large finger, then two, because he knows what he's doing is sweet torture and neither of them want it to end.

Jeez he's good at this... Oh, did he just... oh that feels fucking amazing. Where did he learn... oh yeah, thaaat? I don't wanna know, but I probably should be thanking someone because... Yes, Yes, Yessss! Did I just say that out loud? Oh who cares?

He knows he's good at this, and surprisingly he's not smug, cocky or egotistical about it. It's just a simple fact that he loves women, loves to please them, but never in his entire life has he wanted a woman more, wanted to please her more than he does Kate. And if her soft whimpers, the subtle rocking of her hips and the way her muscles are clenching is any indication, he's definitely doing something right. God, I want to see her come; watch her, feel her, hear her shatter with my mouth on her and my fingers inside her.

Kate is wound tight now, the ragged sound of her own breathing the only thing louder than the frantic thudding of her heart as he shifts the angle and tempo of his fingers, while simultaneously slowing the speed and increasing the pressure of his tongue. That's all it takes and she comes powerfully and blissfully undone, completely lost in a hazy cloud of pleasure that takes minutes to clear and when her eyes finally flutter open, Castle's face is an inch from hers and he's looking at her like she's the most amazing thing he's ever seen.

"Extraordinary," he whispers before kissing her hungrily and she realises he was watching her the whole time and it's kind of a turn on.

"Rick," she breathes, and it sounds desperate and pleading and she doesn't care because she wants him, now.

They are kissing again, Castle's hips in the cradle of her thighs, his impossibly hard arousal pressed firmly against their stomachs as he fumbles with one hand in his bedside cabinet for a condom.

"Oh, thank God," he croaks when he finds two small square packages and immediately tears one open with his teeth.

Kate can't help chuckling at his fumbling haste to remove the contents from its packet and as he shifts off of her briefly, she watches as he rolls the condom on with slightly tremulous hands and her mouth goes dry; a reaction in direct contrast to the growing pool of moisture between her thighs.

He holds her gaze as he slides inside her, slowly and oh so surely, her back arching immediately in a totally involuntary reaction to the feel of him filling her and she's completely awash in delicious sensation. Because oh God, he's inside me and finally we're here and he's moving and it feels so good and the way he's looking at me, touching me... ahhh... yeah... it's... it's perfect. Kate feels her chest tighten and her belly flutter wildly at the intensity of his gaze and she can't help smiling at him, but as they start to find their rhythm, as he moves slowly and powerfully inside her, she kisses him and allows her eyes to drift closed, allows sensation to take over and there's no more talking, no thinking, only the feel of him.

They way she arches off the bed as he glides into the wonderfully slick heat of her almost undoes him, and the way her hips rock into his, gentle circular motions as she grips his back and let's out a low, barely audible whimper, tests every ounce of his barely intact restraint. Because fuck, she's wet and tight and we're already in sync, and now she's smiling at me and it's soft and sexy and... oh God, she's kissing me and that mouth... and Jesus, now her legs are... and she's... it's... C'mon Rick, where's your fantastic way with words now? Who am I kidding, Kate Beckett is in my bed, underneath me with her mile-long legs around me and it's perfect... she's perfect... God I love her.

In every area of their lives they have an undeniable rhythm, a special chemistry and it's obvious in the way they work together, the way they think, the way they almost read each other's minds. It's there during their conversations, in their banter, in their use of subtext, their innuendo, and the way they often finish each other's sentences. And it's undeniable now, in the physical expression of four years worth of denial, unspoken feelings and longed-for touches because they are spectacularly in sync. Every movement, every kiss, every touch is like a perfectly choreographed dance, with the sole purpose being to express all those unspoken feelings, to bring pleasure to the other, to apologise for past hurts and to promise that this is the start of something, the beginning of their always.

Their rhythm is flawless as sweat slickened bodies move in perfect unison. Every caress elicits soft whimpers, desperate cries, almost primal moans; and unwavering gazes communicate trust, unbridled passion and love, pure and unfiltered.

Castle is braced on his forearms, his chest lifted so he can see her and to keep his hands free to touch her, and right now he has one hand between then, his large fingers pressing just above where their bodies are so intimately connected and he has her so worked up that she's about to open her mouth and actually beg him to...

"Not yet, Kate," he whispers huskily in her ear as he withdraws his hand, raising it to join the other, brushing tendrils of damp hair from her beautifully flushed face. They kiss lazily, the slow glide of their tongues in direct contrast to the increasing tempo of their hips and as he moves faster, press deeper she matches his pace.

Despite the loss of his hand stroking her, the tension low in her belly continues to build and she is oh so tempted to just give into it, let him take her back over the edge, back into the blissful abyss he led her into earlier. But no, she wants to lead for a while, set the pace, drive him a little crazy, so she hooks one leg around his upper thighs, digs her heel into his hip, uses her other leg as leverage and rolls them.

Castle yelps a little at the sudden move and there are simultaneous groans of protest as their connection is briefly interrupted, but when Kate splays her hands on his chest, leans in and tugs his lower lip between her teeth and lowers herself over his hard length, the only sounds in the room are mutual gasps of pleasure.

She kisses and nips at his chest, teasing his nipples and she's surprised by the strength of his reaction to it; but that reaction pales in comparison to the one she gets when she pulls herself upright. Hair wild, cheeks pink, a salty sheen on her smooth, naked skin has Castle wide-eyed and staring, visibly trembling; and as he reaches for her, one hand on her hip, the other cupping one breast, she rotates her pelvis and smiles at his sudden, sharp inhalation and the buck of his hips.

"Kate Beckett, naked and in charge. Hottest thing I've ever seen."

They are silent then, eyes and hands on each other, their pace starting slowly, building with every caress, every thrust and Castle can't look away. He watches in rapt fascination at every expression that crosses her face, every movement of her hands, every ripple of her lean muscles and every move her hips make, but when she grabs his hand and presses it to her belly before guiding it to her centre, he falters, can't keep their momentum going.

He presses his thumb to her clit as he grabs the back of her neck, pulling her down, and when their lips meet in a ferocious kiss he rolls her onto her back again. He was trying for smooth and graceful but the movement is a little clumsy and he smiles apologetically. She grins back reassuringly as he settles over her, his mouth moving to her neck, his tongue and breath hot against her flaming skin; and as he slides both hands under her ass, tilting her pelvis up, his whole body presses heavily against the entire length of hers, allowing him to sink deeper.

Kate clutches at him, one hand gripping a large handful of his hair, the other pressing half moons into the slick skin of his back with her fingernails. Oh Jeez, what is he doing? God he's hardly moving, and I can't either but... oh yeah, keep doing that... that's... oh God.

"Castle," she whimpers, her tone begging him for something, and as she teeters desperately close to the edge, she can't help herself; in a voice that's completely foreign to her own ears she breathes, "God, don't stop."

Her words and the way her body tightens around him brings Castle within a hair's breadth of hurtling over the edge they are both balancing so precariously on and he cries out; their movements less in sync, more desperate as they clutch at each other.

"Kate?" It's a question, a plea and hopefully not an apology because the low keening whimper she makes as she clenches vice-like around him brings him completely undone and it takes a moment for him to realise that she's right there with him. Oh thank God is his final thought before time stops and the world shrinks to just this, just them and the tidal wave of pleasure that washes over both of them.

There is a full minute of nothing but ragged breathing in the room; no other sound, no other movement, but as their breathing settles and their awareness returns, Castle takes some of his weight on his elbows. When he looks down at her, Kate's eyes are still closed and he takes that moment to just look at her.

The rush of love that he feels is sudden and fierce and God, he wants to say it, but he hesitates. Don't scare her Rick, just bask in the after-glow for a bit, let all those endorphins kick in and make you all boneless and love drunk. 'I love you' can come later. Maybe after round two. He softly kisses her still-closed eyelids as his thoughts swirl and just as he's about to kiss the tip of her nose, her lips turn up in the smallest hint of a smile.

"I love you," she whispers, and when she hears his soft gasp, her eyes flutter open and green meets suspiciously bright blue.

"That's twice in one day."

"What?" Kate asks, confusion furrowing her brow as she reaches for his face, the hint of tears in his eyes tugging at her heart.

"Twice today the women I love most have made me cry," he says with a watery smile.

"That's because you're a big girl."

He chuckles softly and rolls to his side, arms securely around her so he can drag her with him, and as she snuggles into his side, tangling her legs with his, he strokes one finger up and down the length of her back.

She sighs contentedly and her eyes begin to drift closed. The last thing she remembers as she hovers between wakefulness and sleep is the kiss he places on the top of her head and his low whisper… "Best date ever."

Congrats if you made it to the end. This was considerably longer than the 'T' version, but apparently I have no idea how to edit my smut - pretty much everything that comes into my head ends up on the page. So thanks for reading and I'd be forever grateful for a review.