Crossing lines

He's been tiptoeing this line for far too long, never quite crossing it. Almost two years, in fact. Dancing the tightrope of flirtation without ever slipping off into the inferno beneath. It would be an inferno, too: it would only take one spark to fire the flames and they would blaze.

Maybe, they would flame out. He's sure they would have, even one year ago. Now… well, that's a very different matter. He knows she feels it too, so why she's still running around with that motorcycle riding doctor, saviour, surgeon – smug pain in the ass – completely escapes him. It's obvious he's stringing her along: only seeing her in between his other commitments and leaving her at the drop of a scalpel as soon as anything else comes along. He wouldn't have expected confident Kate Beckett to put up with that, but for some unknown reason she does. Mind you, if he were Dr Motorcycle Boy he certainly wouldn't put up with his girlfriend spending every last hour at her job and pretty much tethered to another, much more handsome and charming man. But for some unknown reason Dr Motorcycle Boy does.

But here on a bright late-February day Castle's just suicidally pulled all of the wires out of a dirty bomb – well, if he hadn't got it right they'd have died anyway – and saved the world and Kate Beckett has thrown herself into his arms and is looking at him with her whole soul in her eyes and he can see the truth: that she wants him, and more than that. She's looking at him as if he's a hero (and maybe he is, but it wasn't exactly deliberate) – and he steps over the line for ever because he's bent his head to her right there in his arms and he's kissed her.

He's kissing her, and the flames are engulfing them. Hard mouth on soft lips, hard body against softer curves over lithe muscle, hard grip around soft pliancy: he ravages and raids and plunders: searching for the response he's known for nearly two years would be there when he does, and finding treasure trove.

An eternity later, some unromantic truck driver honks rudely and breaks the thrall. For avoiding charges of public indecency, perhaps it's just as well. For breaking that moment (or lifetime) of complete connection, it certainly is not. But since they couldn't be any closer with their clothes still on and hands on view, it gives him the chance to move this on.

We did it!, he had meant to say. We saved New York! What he actually says is "Ditch him, Beckett," without in any way softening the hard note of command in his voice. Seems like his subconscious caveman has decided to take over.

"Huh?"

He leans down and murmurs low and dark in her ear, buoyed to bravery and truth by adrenaline and near-death. He's going to live his life: he's going to have it all. Starting right here and now, with her.

"Ditch Josh. You want me and I want you and I'm taking you back to mine now because we are going to do this. So ditch him, because I'm not sharing you with anyone."

She stares at him, dazed, her eyes cloudy and dilated, still held tightly against him as the traffic roars past unknowing how close disaster had been: she's still right there so he kisses her again, predatory and possessive: she the prey that he's caught and trapped and will keep under his paw.

"He doesn't really want you. He sure doesn't love you. You don't want him and you certainly don't love him." He takes her mouth again, hot and sure. "You wouldn't fire up like this for me if you did. Ditch him, Beckett, because you don't cheat and I won't share and you are coming home with me right now."

She's still looking at him blankly, uncomprehending: completely blindsided by his assumption of wholesale domination and the right to order her around. Interestingly, she's not protesting, though if her brain is as fried as his is right now that's no surprise. Maybe the flaming desire has burnt away their everyday masks to reveal a different Castle and Beckett.

"Do it, Beckett." He's uncompromising.

And she does. Pulls out her phone and dials and speaks, briefly and calmly: an undertone of confusion in her voice but she's done it. No-one left in their way.

He doesn't let go of her, trapping her in his enclosing grasp and walking her into the passenger seat of her own car; rifling the keys from her and she's still shocked and silent and wholly acquiescent: all the words she might have used robbed from her by his lips. He drives to his loft: no-one there, all in the Hamptons where he sent them. His loft, his domain, and then to his lair: keeping her in the same close hold as he had earlier, wrapped in his arms and quite unable to escape. Not that she seems to want to escape.

"You're mine now," he growls as he closes the bedroom door behind them. "All mine." He spins her to face him and repossesses her mouth without a qualm or any apology, and she curves and opens beneath his kiss, pliant and responsive, her hands around his neck and locking in his hair.

"Mine," he grates again: no doubt, no reason for disagreement in his voice; his arm firm around her, keeping her pressed into him, against hot hard weight and strength. She shifts a fraction, all that's possible in her position, and suddenly she's perfectly placed right where he wants her, rolling a little, a twist of her hips to rub against him and light the match. It's all it takes, that tiny movement: she's wholly into this, into him.

His kiss turns deep and sure, still hard and searching but less frantic: a statement not a demand. He untucks her shirt from her pants so his hands glide over the smooth skin of her back covering the lean lines of her body: slim but strong, as beautifully and lethally honed as his fencing foils and as fitted to his hand. He spreads his fingers widely across her back and continues to press her closer, a twist and push of his hips in turn foreshadowing the near future, and she gasps and opens her stance a little for him and moves in response. One of her hands moves to his shoulder, whispering across his collarbone to the open neck of his shirt, skipping over the placket to touch him and he loosens his grasp enough that while she is touching him he is opening her shirt and spreading the fabric wide and sliding it from her shoulders so that she's left in a delicate white lace bra that does nothing at all to douse the raging heat around them.

Abruptly, she recovers from whatever stunned compliance he'd drowned her in, and starts to bring her own spin to events. His own shirt is open and missing and that brings them skin to skin, chest to chest and it's electric, the arc sparking back and forth and he can't help himself: plundering her mouth again and dragging her as close as he can bring her: it's possible, probable, that he's left finger marks on her waist or shoulders where he can't soften his grip because he can't take the slightest risk that she slips from his hands. Not this time. Not any more. Never again.

She's snapped into full life, raiding his mouth and nipping on the join of his neck to his shoulder: the slight sting reminding him that while Beckett might have been oddly passive for a few moments, that's not her normal modus operandi at all. Suddenly his normal, confident, full-force Beckett is back and while that's not going to change his own forceful, assertive masculinity it certainly relieves the slight tinge of worry that he was overstepping the line and had somehow bullied her into compliance. But no. They've crossed this line together. They only needed that final push.

He brings his hand round, other hand still at the base of her skull and those fingers holding her head angled for his access to mouth or to elegant neck: marauding across her waist and by feel alone unbuckling her belt, flicking open the button of her pants, dropping the zip and then pushing them off her slim hips to slither and puddle on the floor: she's in mismatched underwear though each piece is individually sexy and the effect is really quite ridiculously arousing because now she looks tousled and as if she hurried out of bed, a final round that she hadn't really had time for leaving her short of time to consider her dress choices. He'll cause her to look like that, often, he thinks, and smiles slowly.

He pulls her back against him with his free hand over her taut rear and grinds against her, showing her exactly how much he's into this, hinting what he'll do for her and with her, and something about still being in his pants while she's in her pretty, mismatched underwear is doing it for him, and from the soft noises it's doing it for her too. She's fighting back, though, and ohhhh he didn't know that he had that nerve there because her single little nip has gone straight from behind his ear to his groin and he can feel her wicked smile as she does it again.

The hell with pants. His are gone as fast as he can dispose of them and then it's mutual hot hands and frantic stripping and they're skin to skin and hardness to soft heat and lifting her up and bringing her down around him and ohhhh it's how he'd thought and hoped and dreamed it might be: inside her and his tongue in her mouth and he can only move a little but it's enough; her hand drops between them and next time it'll all be him but he has to hold her up and slim as she is that takes both arms. He should have pinned her against the door so he had one hand free… He'll remember that for next time.

And then he stops thinking about next time because all there is now is this time and the feel of her surrounding him and the taste of her mouth and her skin and they couldn't be closer: he couldn't be deeper or harder or stronger, she couldn't be tighter or hotter or wetter and simply ohhhhh Kate.

His knees have crumpled, and Beckett has her feet on the floor. Not that she's supporting her weight. Not that he is. Hers or his. The door is supporting both of them. It's just as well it's sturdy. His weakened knees don't stop him making sure that Beckett is snuggled tightly against him. When he can move, there's a nice big bed right over there where they won't have to worry about staying vertical while they explore some more variants on this delicious new game. Only two players needed or wanted. Only these two players.

She's escaping. That's not allowed. No no no. No running away from him. He takes a firm grip around her waist and stops her.

"Stay here."

"Bed," she says, a little slur of heat and desire behind the word. Oh. Okay. Bed. Yes – oh, yes. Why is he even bothering to think about this?

"Bed," he repeats, definitively. "Now." Amazingly, they both manage that without tripping on the scattered clothing on the floor and round their ankles. It's not as if he can focus on anything other than Kate Beckett completely naked in his bedroom and looking thoroughly loved-up already. She'll look a lot more delightfully tousled and ruffled and flustered and sexed out before he's done with her tonight. Not that he intends to be done with her. Ever.

Right now she's stretching luxuriantly across his bed with her dark hair shining and tangling across the pillows and a very come-on smile and posture. He couldn't say he hasn't dreamed of this. He also couldn't say that the reality is not so much better than his dreams. And his dreams were hot. He hadn't had dreams like that since he was a teenager. But since he kissed her in an alley he's dreamed those dreams every night, and here only three weeks or so later he's told her to ditch Dr Motorcycle Boy – and she did – and brought her here – and she came, oh boy did she come – and now she is staying. And if that's primitive, possessive, and primal, well, he really doesn't care. He intends to be very primitive and possessive, starting now.

He stands beside the bed and simply looks down, raking over her with a hot gaze and slow, lazy, predatory smile that says without words you're mine. All mine. Her answering smile is best described as take me, I'm yours. He will. Slowly, and wholly. This line has been well and truly crossed, and by the end of the night it'll be erased.

He sits down and balances a finger between her clavicles. She bites her lip gently in invitation, and flicks the tip of her tongue to wet it. He draws a slow, firm line downward, and her chest rises under it. Her breathing is harder, her mouth a little open, her skin beginning to glisten. She reaches for him to pull him down, but Castle's got other ideas. He catches both her hands in one of his and puts them above her head, leaving her stretched beneath his avid gaze and mouth. He bends down and begins to apply considerable talent and technique to leaving her in no state to think, talk or do anything other than surrender to exquisite pleasure and to him.

He starts at her neck, nibbling delicately, too lightly to leave a mark. After he's had his fill of that – and Beckett is squirming under his mouth and trying to draw in enough breath to finish a phrase that might have started with stop messing around – he moves down a little, dropping teasing little kisses down her cleavage and absolutely not touching her breasts at all. He's deeply proud of his self-control. Beckett is deeply and vocally unimpressed, and it's just as well he spends time in the gym because she's pulling hard against his constraining hand. She's stronger even than he'd expected.

On the other hand, she might be pulling against his strength but she's clearly enjoying the fact that she can't shake off his grip. She's panting now, and twisting to try and bring his mouth where she wants it. Nice to know what she likes… He aims to please. Both Beckett and himself. But not just yet. He's going to please himself for a minute or two – and tease her. By the time he's done she'll be sky high. He really, really likes the thought of Beckett being totally undone by him. She blindsides him so often… time for a little payback. Very, very pleasurable payback.

He kisses a neat little lightweight line down the centre of her ribs and smirks into her skin as she casts imprecations at his head. Then he kisses all the way back up and stops her epithets by taking her mouth just a little roughly.

"Calling me that isn't nice," he says reproachfully. Beckett's excellent outline heaves wrathfully.

"Teasing like that isn't nice either," she gasps out.

"I don't know," Castle smirks. "You seem to be enjoying it." He traces a finger down past her navel and stops half an inch before he should. Her hips lift into the touch. "See?"

"Let go of my hands and I'll show you enjoyable."

"Hm. Let's see. A vague promise that sounds more like a threat… or keeping you pinned down in my bed and having my wicked way with you?" Beckett growls, and has another attempt at freeing her hands. It's rather spoilt by the gasp in the middle as he twines his tongue over a proud nipple. "I think I'd rather have my way."

"And what about my – oh! – way?"

"Nah. In fact…" he pauses portentously… "I don't think you should get your own way this time. You always get your own way. I think you'll like it my way much better. Complete change of role." He smirks. "Just lie back and enjoy it, Beckett." It's just as well he's holding her hands firmly. That gesture, if completed, would have hurt. He kisses her again, and strokes over her stomach, and trickles down to where she so evidently wants him to play, and gives her just a little bit of… encouragement. She bucks into his hand, so he encourages some more. She's so hot, and she's so responsive, and if he just slips a finger in there – oh, that worked. Totally undone and it is gorgeous.

Oh, oh, oh! He shouldn't have lost concentration like that. Now he's flat on his back and – ohhhhhh, this has some definite advantages even if it absolutely was not the plan, because Beckett is straddling him – naked! – and if he simply lifts his head a very little he can reach those beautifully rose-tipped breasts and taste them all over again and – hey, that's not fair. She's moved. Backwards. Out of reach. So unfair. On the other hand – hang on. He's got two free hands. Why isn't he using them?

He pulls her forward, lifts her up, and places her back just where he wants her. Then he slides her a little forward, a little back, and oh her slick heat feels amazing against him. She leans down and this time she's raided his mouth till he can't do anything but groan. His brain is fried.

His body is not fried. His body has some very clear instincts. These instincts flip them over, pin Beckett to the sheets, and surge into her. She moans and lifts to him, hauls his head down and robs him of his kisses and breath and sounds as he takes hers. He slips one hand down between them, desperate to bring her over before he loses himself completely, seeks and finds and touches and sends her screaming and shattering and he breaks too.

He's still clutching her when he recovers. She curls in, peacefully.

"Mine," he purrs contentedly into her ear. An eyebrow quirks. "My Beckett."

"Treading a thin line there, Castle."

"Crossing it. I'm sure I can find some more lines to cross. Starting with this one."

He draws a line straight through her soaking centre and follows it up with avid mouth and tongue. She's screaming in moments.

"Or maybe this one?" He adds fingers to the mix, and has to hold her still.

"Or maybe this one?" and he thrusts home again and waits till she's squirming around him and demanding, then pleading, then outright begging that he move, and then finally he moves body and hands and she shatters again and then he can.

Eventually, he finds some breath.

"No matter how many lines you try to draw, Beckett, I'll spend a lifetime crossing them."

Fin.

Thank you to all readers and reviewers. Happy Thanksgiving to all those who celebrate it.

This was a prompt from Mobazan (who else?) "He would tip-toe if he had to, but he had to take the step" which, as ever, mutated. This is sheer fluff.

Trolls will not be given airtime.