I was planning to keep these one-shots T rated, but then this happened. If/when any of these other scenarios end up being M rated, they'll be posted here.

I haven't written anything M rated in like 4 years, so hopefully this doesn't suck.

#1: What if… Castle responded to "why don't you two just drop your pants and get it over with" with action?

Prompt by Lou

"Oh for God's sake," Kate snaps, can't even believe she's about to say this, "why don't you two just drop your pants and get it over with?"

"I'm game," Castle replies without hesitation, already reaching for his belt buckle. He loosens the leather strap, unbuttons and unzips his jeans, all while both Beckett and Will look on in semi-horror. The pants fall from his waist, dropping to the floor around his ankles and leaving him standing next to her desk in his boxers. Boxers that don't do a whole lot to hide the obvious bulge between his legs.

Okay, so he's fairly well-endowed, it would appear.

Kate closes her eyes, forces herself to be annoyed. "Castle, what the hell are you doing?" she finally snaps, hoping she's managed her usual degree of authority.

"Exactly what you suggested," he answers with an unaffected shrug. "Though it doesn't work as well when one of us isn't willing to participate."

She huffs in irritation, because this is just beyond ridiculous. "It was obviously rhetorical. Pull your pants back up."

He does, and Kate resolutely doesn't watch as he re-situates his jeans low on his hips and fastens them, re-buckling his belt. But as the day wears on, she can't banish the memory from her mind, or the image of the silk-covered bulge, hidden by just a thin layer of fabric. It's been a while. Longer than she'd like to admit. She has no doubt it would be…


She's not going to sleep with Castle.

But her traitorous mind seems to have other ideas, and when she walks into the room as the FBI tech is wiring him up and catches a glimpse of his bare torso, it only piles on to her growing desire.

Damn it.

She wants him. Despite his constant bickering with Will, despite the fact that he irritates the hell out of her, she wants him. Badly.

He finds her in the gym the next afternoon following her shift, after Will is gone and the paperwork from the case is complete. She thought he'd left, and she'd come down here to pound her desire and frustration into the punching bag, but Castle's reappearance erases what little progress she's made.

"What do you want?" she huffs.

"I think the better question is what do you want?"

Kate hurls her fist at the bag, connects with a satisfying thwunk. "Excuse me?"

"It's okay, Detective, you can admit it," he says, approaching her far too confidently, eyes twinkling, smug eyebrow raised. "It's just us."

She winds up, swings a foot at the bag this time and sends it jolting away from her before it swings back and she catches it in both hands.

"Don't you have somewhere to be?"

He shrugs. "Not at the moment. Besides, I think you're glad that I'm here."

Kate snorts. "Absolutely not."

"Really?" he asks, eyeing her up and down, gaze momentarily stopping on her heaving chest before returning to her face. "Then why have you been staring at my crotch all day?"

Her face gets hot. Very hot. Crap. He noticed that? She thought she was being subtle.

"It's the silk boxers, isn't it?" he teases. "They're so soft, you've been dying to touch them."

Kate turns her attention back her workout, lands two more punches. She's not thinking about his underwear. Or what lies beneath. She's not.

She steps back, turns in preparation for another assault on the punching bag, and winds up right in his arms. "Or maybe," he utters, low and sexy, both hands cupping her shoulders, "you're dying to see what's underneath."


She's so screwed.

He's close, so close, and he's touching her bare shoulders, thumbs flirting with the straps of her tank top and palms so soft and smooth on her skin. Her eyes drop to his crotch without permission and she forces herself to drag them away because this is not helping, but then they land on his chest – the surprisingly toned chest she caught glimpses of yesterday afternoon – and that's not helping either.

Kate drags her gaze up to his face, but that proves to be the worst of all because his eyes are wide, pupils blown, the blue of his irises relegated to a thin ring around the edge of the wild darkness. He's looking at her like he wants to devour her.

"Castle," she protests, except it isn't a protest at all. It's breathy and encouraging and far too sexy. One thumb releases the edge of her tank top, strokes up along the curve of her neck. She bites her lip to repress a shudder, watches his eyes instantly home in on the movement.

"Tell me to stop," he murmurs as he leans in. He swallows and she watches it ripple down his throat, and this is a terrible idea but she doesn't want him to stop. She wants to press her lips to his adam's apple, feel the scratch of his stubble against her skin.

They shouldn't do this. There are so many reasons this shouldn't happen, but they all vanished from her mind the moment his hands landed on her skin and, in the moment, all she wants is him.

"Don't stop."

His lips descend the moment the words leave her mouth, hot as they slick over hers. His hands slide up to cup her jaw, tilting it enough to deepen the kiss and holy hell, this has escalated so quickly. Kate reaches for something, anything, winds up with two handfuls of his shirt. She tugs and he stumbles closer, backing her into the punching bag. He tears his lips from hers, redirecting them to her neck, and she feels her knees weaken as he sucks on her pulse point. Castle drops his arms to catch her around the waist, tugging her closer, and she can feel his need pressing against her hip.

"Oh God," she breathes as his tongue dips into her collarbone, teeth scraping gently against her skin. Her knees buckle and it's only his grip around her waist that keeps her from crumbling to the ground. He's hot and pulsing against her thigh and he presses into her as she slides over him.

Castle groans, hands spreading over her ass, pulling her impossibly closer. One hand moves up, finding its way under the fabric of her tank top while the other flirts with the waistband of her yoga pants, dipping beneath and quickly discovering the thin strip of her underwear.

She's been tugging at his buttons for… a while? She's lost all concept of time. But she can't focus, and she still has wraps on her hands from her workout, and she's only managed to free one of the buttons. Kate gives up on them, yanking his shirt from his jeans and reaching for his belt.

His right hand has found the edge of her sports bra now, fingers tracing the line of spandex around her side to graze the edge of her breast. His left hand is following a similar path around the other side of her body, fingers traveling along the edge of her underwear until they reach the front of her hip and dip beneath the fabric to swirl around the point of bone. He tugs at the waistband of both pants and thong, and it's that movement that finally snaps her back to reality.

"Castle." The only response is the hum of his lips against her neck. She tries again, receives a similar response. "Castle," Kate pants, stronger this time and coupled with the press of her palms against his chest.

He stumbles back, looking both heated and confused.

"We can't do this here."

"Right." He pulls his hands out of her clothes, starts to move back, but she fists her hands in his shirt again, stops him before he can move away.

"Locker room," she hisses, tilting her head to the opposite wall of the gym.

His hands are back on her in an instant; he hoists her off the ground and she wraps her legs around him in a move that's far too synchronized for two people who have never done this before. Castle grunts, loses his balance slightly and they both teeter into the punching bag before he rights them and crosses to the locker room in large, determined strides. Kate loops her arms around his neck and focuses on freeing her hands, hastily unwinding the wraps and tossing them to the ground.

He kicks the door open with a foot, and the moment they're inside he has her pressed up against it, pushing it shut with her back. Kate reaches behind her, fumbling for a moment before she finds the lock. It clicks into place and from there it's fast and furious. She unbuttons and unzips his jeans as her bare feet find purchase on the cold concrete floor. Her knuckles brush against his hard length as the metal teeth release, and the pants fall to his ankles. Castle stumbles as he toes off his shoes and socks and steps out of the confines of the denim. Both hands slide up the back of her tank top and Kate raises her arms, allows him to peel the fabric off her sweaty skin and toss it aside. She shifts her focus to his shirt once again, finds it easier to maneuver the buttons when his lips aren't on her skin, but this is not okay because she very much wants his lips on her skin again.

Right now.

The shirt falls open as his hands slide beneath her waistband, palms spreading across her ass before his hands curl around the fabric and tug. By mutual silent agreement they switch jobs, Castle focusing on sliding his shirt off his arms while Kate shimmies out of her pants, leaving them both heaving and flushed and clad only in their underwear.

There's a moment of silence, some mixture of shock and oh my God, this is happening, but no, this isn't supposed to be tender or romantic. So Kate reaches for her bra, crossing her arms to grab the elastic band and pulling it over her head in one smooth movement that leaves Castle gaping. She reaches for his waistband next, stretching it out and over his erection before tugging the boxers down his legs, revealing the part of his anatomy that started it all.

Kate swallows hard.

Oh, fuck.

"Like what you see?" he utters with a raised eyebrow.

Kate levels him with a glare. Smug jackass.

He reaches for her thong, slips his fingers beneath the fabric and tugs it down her legs. "You know, you're sexy when you're pretending to be mad at me."

"I'm not pretendi…" she begins to protest, but then his fingers are on her and the words die on her lips because, yeah, she can't really be mad at him when he's making her feel like this. Her head falls back against the door and Castle's lips descend to her neck as his fingers swirl around her center.

"You're so wet," he groans against her skin.

Two fingers slid inside of her then and she can't bite back the whimper that escapes because oh God, he's good at this.

His lips trail across her collarbone, down to the curve of her breast, and she wraps her arms around his neck while pressing back against the door so she can lift one leg and loop it around his hip, holding him close and opening herself to him. He's still working her with his fingers, the heel of his hand pressing against her clit with the change in position, and then his lips close over her left breast and a shudder wracks her entire body. She's already so close.

Kate slips an arm between them, wraps lithe fingers around his throbbing length and strokes once, twice, before he's pulling his lips away from her skin on a groan. "God, Beckett."

She brushes a thumb across his tip and he twitches in her hand as his hips buck into her. Okay, so he's close too then.

"Condom," he breathes, eyes heavily lidded as he watches the movement of her hand as she lazily strokes him again from base to tip.

"I'm clean," she replies. "And on the pill."

"Me too," he answers automatically before lifting his eyes to find her gazing at him in amusement. "To the first part."

She tightens her other hand around his neck in response and presses off the ground with her foot, trusting him to catch her even though they have no right to be this in sync. He does, large hand spanning her ass as her right leg joins her left around his waist.

Kate strokes his tip along her core, coating him in her wetness before she pauses with him at her entrance, and for a split second they're suspended in this moment that she knows was inevitable; and then he presses into her and she sinks down over him until their hips are flush, and oh God, why did they wait so long to do this? He's hot and solid inside her, filling her completely, and he gives her a moment to adjust before sliding out and slamming back in. Her inner muscles flutter around him as her eyes flutter shut, and he must notice because he repeats the movement again. And again.

Kate drags her eyes open to find him gazing at her in awe, eyes awash with something that looks far too much like adoration. So she twists her hips on his next thrust; his eyes go wide and the hunger returns, and before it has a chance to disappear again she leans in and captures his lips with her own in a kiss that's hot and sloppy and thrust of his hips presses her harder against the door and she knows she's going to be sore tomorrow but she can't bring herself to care when he's devouring her lips and thrusting into her in a rhythm that's already beginning to falter.

"I'm so close," she whispers against his lips.

Castle slips a hand between them, finds her clit. One, two, three swipes and she's shattering around him as he pulses inside of her, and then they both slide to the floor in a sweaty, sticky, breathless tangle.

Holy shit.