A/N: Okay… I was going to get a few months into this series before unleashing this chapter on you guys, but I'm running short on concentration this Friday. This chapter has been waiting patiently to see the light, so I polished it up a little bit and decided to just put on my big girl panties and post it.

This is probably the most extreme idea I have, so if at any point you're not feeling it, please just stop reading this chapter. It's not going to be for everyone. But please don't run away forever, the rest of the series is going to be just as lovely and emotional as the previous chapters. Next week coincides with 'Still', so I'm going to think of a fantasy that ties in nicely as a post-ep for that very intense episode.

Without further ado, I'm going to scurry over to the corner and hide in abject shame now for having such a naughty naughty imagination.

WARNING: Rated M.

Fantasy Fridays
Chapter Six: Richard Castle, M.D.

The Amazon box arrives at the precinct looking more innocent than it has a right to. When the UPS man lets LT sign for it, Castle visibly blanches.

Beckett looks up from her paperwork and startles at the wild panic on her partner's face.

"You okay, Castle? Or should I call you Casper?"

"Hold on, Beckett I just need to, um, get that package."

She watches, bemused, as he skips away from her and pries the cardboard box from LT's paws. She can't make out what they're saying over the rings and murmur of the bullpen at rush hour, but it looks like LT's giving Castle a thorough grilling about what's inside the box. Castle waggles his eyebrows and suddenly LT throws up his hands, giving the box a disgusted stare.

Castle returns to Beckett's desk and shoves the package into the bottom drawer. He's flushed, and his eyes dart around the room, checking if anyone else noticed the exchange.

Beckett smothers a grin. "Putting things in my drawers without asking, Castle?"

His eyes snap to hers, smoldering. "You like it when I put things in your drawers," he says. He's using the tone of voice that makes her need to cross her legs. The one he's not supposed to use at work, but does anyway. Every day. Several times a day.

"So…what did you tell LT was in the box?"

"A year's worth of Jugs magazine and some lotion."

Beckett chokes on her own spit.

"What? I'm supposed to be single," he hisses.

"Jugs, Castle, really?" There's not a trace of insecurity in her voice, just laughter. She's not concerned about her own um, assets, and knows without a doubt that Castle thoroughly enjoys hers. Really thoroughly.

Castle drops his voice even further. "That's not really what's in the box. You know I have very little use for porn these days. Coffee?"

He stands and picks up his mug, but leaves hers on her desk. It's their sign for meet me in the break room for inappropriate banter and touching. She follows, eyes rolling at the memory of the day he created what he calls his 'cleverly devised Bat-Signal.'

They stand side by side at the coffee machine, hips bumping, their familiar, delicious low hum of electricity buzzing louder now.

Beckett's the first to speak. "I'm going to take a wild guess and say that the contents of that box are related to our plans for this evening."

"Spot on as usual, Detective."

"You going to tell me what's in there, or does it take two people to use the milk frother these days?"

Castle rolls up his sleeves, and Beckett has to bite her lip not to reach out and stroke the muscles that play under his skin as he works the coffee machine like an expert barista.

"Tonight I'd like to make one of my more ridiculous fantasies come true. It's one of the scenarios I put us in fairly often before we got together."

Beckett blushes. Before they started dating, she'd guessed that he'd spent quite a few evenings thinking less than pure thoughts about her, keeping himself company with the stroke of his own hands. A few weeks into their relationship, he'd confessed just how often. And just how impure. The muscles in her thighs tighten involuntarily.

"And which scenario would that be?" Her voice is embarrassingly hoarse all of a sudden.

Castle angles the frothing wand into the jug of milk and turns it on, the spluttering, mechanical whir drowning out his words to everyone but her.

"Well … I'm a doctor. And you come in for a routine appointment."

Beckett's cheeks flame with conjured images of Castle in scrubs. Of Castle pressing a cold stethoscope to her bare chest, listening to how he makes her heart stutter.

"You got a lab coat in there?"

"Yes," he states, simply. Her stomach tightens with arousal.

"But. Beckett. In my fantasies, I'm not just any doctor. Let me tell you what else is in the box."

He moves behind her then, ostensibly to reach for her cup, but he stops with his arms spanned either side of her. He works around her like she's just the empty space between him and the counter, arms reaching, brushing, bustling. On each pass he gets closer, until his breath is hot on her ear and she can feel him - especially one very warm, firm part of him - pressing against her backside. On each pass he drops a different word.

"Lab coat."

"Latex gloves."

"A water-based lubricant."

What?

"Stirrups."

Oh, holy fuck.

"And a speculum."

She's frozen to the spot. If she moves, if she breathes, she's afraid she'll ignite. Castle steps away and sets her perfect latte down on the counter. There's only one coffee; he didn't make himself one.

"Kate. I'm going to go home and get set up. Text me when you're on your way."

He squeezes her hip, lets his fingers trail across the small of her back as he leaves.

She starts breathing again when she sees the elevator doors close behind him. A shaky sip of her scalding hot coffee brings her back to herself. He knows better than to do this to her at work. Castle has just got himself into big trouble, and he probably knows it, but is counting on this burning hot fantasy to keep her mind off his transgression. Letting her indignation wash the arousal away, Beckett starts plotting her (sexual) revenge.

A gynecologist, hm? She can definitely work with that.

"A um … Miss Katherine Beckett, please?"

Castle pops his head around his bedroom door as soon as Beckett steps into his foyer and shucks her coat. He's got a clipboard in his hand. He looks kinda … respectable. She'd half expected him not to be wearing anything under his stark white lab coat, but he's in the same dress pants he had on earlier and a powder blue button down.

And a name tag that reads Dr. Richard Castle, M.D.

It makes her want to burst open with light, stunned by how much she adores this silly, ridiculous man.

"That's me," she says, holding up a hand awkwardly like a kid during roll call on the first day of school.

"Right this way, please."

Beckett follows him into his bedroom. Scratch that, the examining room. He's actually hung hospital curtains around his bed. They're sea foam green and patterned with the 'edgy' geometrical shapes of the 80's.

The man does not do anything by half.

Somehow, he's attached metal stirrups to the end of the bed, and he's put a pair of Beckett's own fuzzy socks over them. There are a few pillows stacked in a slope, and she assumes it's so she can watch him work.

"Here's a gown for you to change into. Just let me know when you're ready."

Castle pulls the curtain closed and starts bustling around, whistling over the sounds of metal clinking as he prepares his tools. Kate grins and starts peeling off her clothes. The hospital gown is stereotypically billowy and useless, but for once she doesn't mind.

Beckett lays down on the bed and presses her knees together before calling out to him.

"Um, Dr. Castle? You can come in now."

Castle draws the curtain back and wheels a small metal table closer to the edge of the bed.

"Fantastic. Thanks for filling out the questionnaire the nurse gave you in the waiting room, it saves us a bit of time. I'll just start with a breast exam, if that's ok?"

"Sure."

Kate bites her lip and stares up at the ceiling, trying not to smile. She loves that he doesn't do anything by half, staying perfectly in character as he carefully pulls open her papery gown and exposes her breasts. He's done his research. Goodness knows he loves his research. And goodness knows she loves him.

"So, Miss Beckett, what do you do for a living?"

"I'm a homicide detective."

"Interesting," he says, tone detached, like he couldn't possibly care less, when in reality she knows it's the thing he finds most fascinating about her, the thing he's been intrigued by since day one. Moment one.

Castle's warm palm slides over one breast, gently pressing and cupping and probing. It's clinical, methodical and somehow … incredibly hot. He's trying not to stare at her, because that's not what doctors do, but he's failing miserably, and when her skin tightens, nipples responding in a way they never have in a real appointment, he lets himself make his first unprofessional move.

Just before he moves his hand from one breast to the next, he lets his thumb graze across the tip, once, twice, thrumming her, and then he's gone.

Kate holds her breath to keep from gasping and tries not to arch her back to meet his hand when it covers her other breast. He applies the same tender pressure to it, from every angle. At this rate, he won't be needing to use that bottle of lube on his little tray.

"Hmm…" Castle peers down at her nipple with a furrowed brow. "Just need to check - "

He trails off as he circles his fingertips over her, lightly enough to bring her more erect, then he gently gathers her skin between his thumb and forefinger, rolling and pulling this way and that, acting like he's spotted an aberration. Normally, she'd laugh, but she's too swamped with desire even to smirk.

"Thought I saw something, but it's all okay," he reports. "Now if you'll just scoot down a little further and place your feet in the stirrups, I'll start the pelvic exam."

He turns away and Kate uses the moment to take a few deep breaths to collect herself. In an actual doctor's office, she would pull her gown back together to cover her chest, but she leaves it open, partly to tease him but mostly to cool herself down. It had been really, really hard to just lie there while he touched her, and it's only going to get worse.

Castle turns back to her and she realizes there's something else in the room that's really, really hard.

"Okay, if you can just - "

Kate lets her legs fall open, wide, before he can finish his sentence. He gulps, jaw going slack. She loves the effect she has on him, the power she can wield with just her body, and she can't help the self-satisfied little smile that's creeping onto her face.

He regains his composure, but his voice is an octave lower when he speaks. "I assume you've had exams before, but I'll walk you through this anyway. I'll just press on your lower stomach; tell me if you feel any discomfort."

Castle places his fingers to the soft skin just under Kate's belly button and presses, moving from side to side. He's really selling his performance, and she wouldn't put it past him to have called in a favor with one friend or another and actually shadowed a gynecologist so he'd get this right.

"Nope, everything feels fine," Kate reports, her voice husky and sexier than she intended.

Castle nods. "And now I'll insert the speculum and have a look around."

Kate has to close her eyes. He's about to put a foreign object inside her, and that in itself isn't new, but it's never been a medical implement and she can't deny that this whole thing is a little bit weird.

When the cool metal slides into her, she realizes that weird is about to get her off. He takes his time as he presses into her, then he tries to make the most of the moment by shifting around, pulling back a little and pressing in again, and oh, she finds herself wishing that he'd just get rid of the bedside manner and start sliding the tool in and out in earnest. But instead he opens the speculum, spreading her wide, but the emptiness is so unlike the way he spreads her with his own body.

She hears his breath catch and she almost lets one foot drop from the stirrup down to his lap to seek the evidence of his arousal.

"Have your previous doctors ever told you that you have excellent natural lubrication?"

Well, that's one way to put it. "God, Kate, you're so wet," is what she usually hears from him.

"Not my doctors, no," she responds, eyebrow raised.

Too soon, he's pulling the tool out of her. She whimpers softly, starting to get impatient. When's he going to deviate from the textbook?

"Now I'll do a manual inspection."

He turns around and puts on a pair of blue latex gloves just like the ones they wear at crime scenes. That shouldn't turn her on, right? Castle ignores the bottle of lube this time. He looks up at her as he slides two gloved fingers into her, and the air crackles, their characters falling away for a moment as they connect purely as Rick and Kate.

Castle uses his other hand to press down on her abdomen, and she holds her breath. He must be about to touch her poor ignored nerves, he must be about to let go. She's begging him with her eyes.

He strokes his fingers around, swirls, and she watches as his own eyes darken with lust.

And then he withdraws.

"Happy to report that everything looks fine, Miss Beckett."

What the…? Did his fantasy seriously not involve a happy ending? Well, too bad, hers does.

"Actually, I had a quick question, Doctor Castle."

"Oh? What's that?"

Kate widens her eyes in feigned innocence. "I think there might be something wrong with me. I keep reading about these G-spot things in magazines, and I tried finding mine, but I didn't have any luck. Can you check for me? Show me where it is?"

Castle swallows. Hard.

"I'd be happy to have a look."

He slides his still-wet fingers back into her, thrusting lazily a few times just for fun, and she clenches around him instinctually. He makes a show of searching for the patch of skin inside that makes her legs twitch and his performance is pretty convincing, considering he's known exactly how to find it in under three seconds since mapping her on the first night they spent together.

"I think it's right here, Miss Beckett, just about an inch and a half in," he says, pressing up maddeningly.

Beckett tries to get her erratic lungs under control. "Gosh, this is really embarrassing. Can I have an … um … orgasm? Just from touching it?

"Not just from touching, you have to … stimulate it."

Beckett's voice slips from virgin to vixen. "And can you tell me how to stimulate it, Doctor?"

"I think it'll be easier if I just show you," he purrs. "In the name of sexual health, of course," he adds in his Doctor voice.

Castle slides his fingers in and out, slowly, a dozen times, before returning to the spot and circling hard. He works her like a professional, watching as her knees knock together and her bare chest flushes with desperation. He knows he can get her off like this, but he also knows how much higher she'll fly if he adds a bit of external stimulation.

"Miss Beckett?" he asks, fingers still working in her.

"What?" she grits out. Her composure is slipping and she's almost forgotten where they are, her whole world narrowed to the sensations he's creating in her.

"Sometimes it helps if the clitoris is stimulated as well. May I?"

"God, yes."

He doesn't need any more encouragement than that. He leans down and flicks his tongue against her clit, strumming the tight nerves as he massages the corresponding internal muscles. She ripples around his fingers.

"Oh, fuck, Cas - Doctor," Beckett pants, "that's amazing, that feels amazing. Don't stop."

The room is charged with their frenetic energy, full of the soft, intimate sounds of his tongue meeting her flesh over and over again. She's about to come, and hard, but it's his fantasy and she doesn't want to be selfish.

"Doctor, I think I need more," she pants. "Deeper."

Castle obliges, plunging his fingers further into her.

"Not enough," she gasps. "Don't you have anything … longer?"

Castle lifts his head, his mouth soft and wet, eyes twinkling. Good. He's caught on.

"Well, there's always me, but there are strict rules about doctor-patient contact," he says, eyes wide with faux shock and concern. "I wouldn't want to risk my license."

"I won't tell," she breathes.

"Maybe I could make an exception, then. After all, sexual education is very important."

Castle stands up and kicks his rolling stool across the room. It hits the wall and clatters. He unzips his pants and pulls himself out without ceremony, and Beckett props herself up on her elbows to watch. She's still in the stupid gown and her feet are still in the stirrups, and he looks just as ridiculous in his lab coat, hand wrapped around himself and stroking once, twice, taking the edge of the unbearable ache.

His gaze burns into her as he pulls her hips right off the end of the bed, then he clamps his hands around her ankles and angles his body towards her.

"Are you sure about this, Miss Beckett?"

"Ver-" the breath leaves her body as he shoves into her. They both moan. It's her favorite part, that first intrusion, that exquisite thrust that sends shards of tingling pleasure ripping through her. They're so good together, so good. He's learned her, knows her better than she thought it was possible for someone to know her. It's always the perfect pace, the perfect rhythm, the perfect angle.

He must be reading her mind, because he stops, just for a moment, and when her eyes lock on his, demanding, he moves once, so forcefully, so abruptly that her body moves a foot up the bed and she comes hard around him, and later she'll wonder how every orgasm with him seems longer and harder than every one before. It's a kaleidoscope of bliss, her nerves bursting as tingling stars rush through every muscle in her body.

Instead of going limp, it's one of the rare ones that rev her up, drive her nuts, and she might be on the bottom but she's doing all the work all of a sudden, like some woman gone wild, and Castle trembles above her for a moment before he gets his balance back and leans down to devour her mouth like he's devouring her body.

They keep the blinding pace up for an insane amount of time, rolling and twisting and chasing the rush, until her skin is a uniform of blotched pink and red, until the flopping lock of hair on his forehead is dripping. When it's like this, sometimes it becomes an unspoken challenge as to who can keep the frenetic pace the longest, who looses the rhythm first, whether because they can't breathe and their muscles are failing or who goes over the edge first, and this time it's Castle, Dr. Richard Castle, M.D., who loses both at the same time and collapses on her as his hips jerk frantically, emptying wholly, and the feel of him trembling and gushing sets her off again.

When she catches her breath, when the hideously patterned curtains fade back into focus, she starts giggling. She claps a hand over her mouth, another gripping tightly on his slick shoulder, trying to stifle the shakes of her laughter.

"Katherine Beckett, why are you laughing at me?" he mumbles, his head buried hotly in her neck.

"Not at you, babe. Not at you." She shifts and her foot hits one of the stirrups, and she laughs out loud this time. "I just can't believe we did that."

"I thought it was pretty fun."

"Oh, don't get me wrong, I did too. You, uh, better put this stuff in our box, you know."

Castle pops his head up, a huge, boyish grin on his face.

"You'd do it again?"

"Oh, absolutely, Dr. Castle."

?!