Author's Note: Today's #CastleThemeDay theme is holidays, so I told Lou (inkycoffee) that I would accept a smutty but not fluffy holiday prompt. This prompt fill turned out pretty fluffy anyway, which is definitely and absolutely all Lou's fault.

Prompt: "In S4, Christmas happened between Cuffed and Til Death Do Us Part. What if C&B wake up in bed together after the Precinct Christmas party, thanks to a combination of mistletoe and wine?" Lou's prompt did not specify that they wake up handcuffed together, but I choose to believe that it was implied. That's my story and I'm sticking to it.

Kate Beckett woke up with a hangover and a dreadful feeling of déjà vu.

Squeezing her eyes shut against the too-bright glare from the window, she focused on her other senses. The feel of a soft surface beneath her body, like a mattress. The cold bite of metal around her wrist. The soft breaths, warm body heat, and musky male scent of her partner.

Oh God, she was handcuffed to Castle...again.

"Castle!" she tried to snap sharply, but it came out more of an agonized groan. Pain throbbed through her skull as she reached over clumsily with her free hand and shoved at what might be his shoulder, her eyes still closed. "Castle, wake up. We're cuffed together again."

"Wha-?" he snuffled, and she heard a sharp indrawn breath. "Tiger?!" he exclaimed, suddenly sounding very much awake.

"No. I don't think so," she replied cautiously. Her mouth tasted like a grandfather's mothball-filled sweater, and her voice came out as raspy as that same grampa after a pack-a-day lifetime.

"Beckett?" said Castle hesitantly. "Uh, is this, is this your bedroom?"

"What?" Her eyes snapped open, and she groaned at the stabbing pain, quickly closing them again. But she had seen enough in that brief glance to know that he was right. "Oh my God. We're in my bed. What are we doing in my bed?" she demanded, her voice unpleasantly shrill.

"Um." She felt Castle shift on the bed, pulling away as best he could with their wrists cuffed together. "Um, Beckett, you're naked."

Panic began to rise and she pushed it down carefully. Breathe. Breathe. Oh shit, she was naked. Naked in her bed and handcuffed to Castle. Did they-? Slowly she cracked her eyes open, waited for them to adjust, opened them a little more. She peeked over at Castle, who had his own eyes squeezed shut in a grimace of pain.

"Castle. What do you remember?"

"Uh." There was a contemplative pause. "Um, the precinct Christmas party. Oh my god, Beckett, it's Christmas Eve Day!"

"Focus, Castle," she groaned. "The Christmas party." She concentrated. "Oh god, wine. There was wine." She reached out again and smacked his shoulder, hard.

"Ow! What was that for?"

"You brought the wine to the party. This is all your fault."

Ten Hours Earlier

"Great party you guys put on here," Castle said, raising his voice slightly to be heard over the sounds of the 12th Precinct's unofficial barbershop quartet singing Jingle Bells. "Shame about the mistletoe."

"What mistletoe?" Jenny asked, looking at Ryan in confusion.

"There isn't any," the detective explained to his fiancée. "Not allowed any more in precinct houses. There was a memo."

"Spoilsports," Castle grumbled, refilling Beckett's wine glass.

"Aw, you don't need mistletoe to get a kiss, Castle," Lanie teased with a twinkle in her eye. Beckett's eyes widened and she tried to signal her friend with an urgent head-shake, but Lanie ignored her, smirking at Castle and adding, "I'm sure Javier wouldn't mind."

Esposito spluttered messily around his slice of pumpkin pie. Castle merely smiled.

"That's okay. I'm sure I'll survive."

A while later, the bottles of wine that Castle had brought were empty, and Beckett was teetering slightly on her heels. "Time to go home," she announced to the mostly-empty room. "Night-night, everyone."

"Wait," said Castle, struggling to his feet from the chair beside her desk. "I'll walk you up. I mean down. I'll walk you down, Beckett. You shouldn't be drive, driving. Driving. Drunk."

"Not drunk," she denied, getting her arm into the sleeve of her coat after only three tries. "Not driving either. Taking a cab."

"Share a cab?" he said with a hopeful puppy-dog expression, so she took his arm and they stumbled together toward the elevator.

Holding Castle's arm and walking an unsteady line across the lobby of the precinct house reminded Beckett of another time they had walked that way, except they weren't drunk that night, were they? Just pretending. So it wasn't real. Not a real kiss.

Suddenly she was in a taxi, feeling a little dizzy from having fallen into it, and still hazily thinking about alleys and being pretend-drunk and kissing Castle. Except that now she was drunk for real, and there was no alley, no guard. No kissing.

There could be kissing, though. Castle loved her. She knew that, because he had said so. Oh, but that was a while ago, wasn't it?

"Castle?" she lisped, rolling her head away from the taxi window with some difficulty, finding him with her half-unfocused eyes. He was leaning against the opposite window, blinking blearily.

"Yeah?"

"You still love me, right?"

"'Course," he replied immediately, nodding his head up and down, up and down, carefully, as if it might fall off.

Good. Oh, good. "Well," she said, slightly miffed, "then don't you want to kiss me?"

He looked at her then; made an effort and focused his eyes on her face. "Can't," he said mournfully. "No mistletoe."

"Oh. Right." Somehow she had a vague feeling that there was something wrong with that logic, but she couldn't put her finger on the problem. "I've got mistletoe at home, though. In my 'partment."

"Really?" He brightened up at that. "You do?"

"Yep." She nodded, and continued nodding because it made her head feel so funny. She might have giggled a little bit. Wait, no. Kate Beckett didn't giggle. No. Never happened.

Then they were out of the cab and stumbling up the stairs to her building, weaving their way into the elevator, bumping their hips against each other and laughing a little. Somehow they were outside her door and she fumbled her key into the lock and let them in.

Then they were inside her apartment and she stared at Castle in confusion. "What?" she asked, although he hadn't said anything. He looked confused too, and it was adorable.

"What?" he repeated. "We, there was something. You had something. I needed - what was it?" Suddenly he gasped, comically with bulging eyes and jaw dropping. "Oh! Mistletoe!"

"Oh! Yeah." She dropped her purse and coat on the floor and wandered into her bedroom. Mistletoe. Mistletoe. It was here somewhere. It had come with the wreath that she'd bought for her front door. Ah, here it was.

She stood with the small sprig in her hand, staring at it. Wait, there was something else. Something she very much wanted to show Castle. Oh yes!...She turned and opened a drawer.

A few minutes later she made her way back out to the living room, barefoot now and a little steadier on her feet, but still definitely drunk. Castle. Was Castle here? The mistletoe was still in her hand, but where was he?

Oh, there he was, standing by the kitchen island, looking half-asleep. "Castle!" she exclaimed, and his eyes popped fully open in startlement.

"Beckett? What took you so long?" He blinked rapidly. "Did you find it?"

"Found it!" she agreed triumphantly, holding up the small sprig of mistletoe. She pitter-pattered over to him and held the mistletoe high, above his head. But that was awkward and would make her arm sore soon. So she put the mistletoe on his head, neatly resting atop his hair.

It looked so silly that she burst out laughing, giddy, and he chuckled too, and then he put his arms around her and his warm soft mouth came down on hers and she swallowed her laughter in a heated gasp.

Oh shit. Castle. Drunk. Kissing. She was drunk and kissing Castle. So good. She could feel her own throat vibrating with moans of pleasure. His arms were strong around her back, pulling her close against his warm hard body, and her fingers were in his hair. Oops, that was the mistletoe. She had knocked it off and it fell down, maybe. Not sure. Didn't care.

Castle's tongue was on her lips, tasting, asking, and she remembered this; she opened her mouth to him. Oh God, his tongue. Touching her tongue. She tasted the wine again and it was so good. That must have been some expensive wine. It had gone down so smoothly. She had drunk quite a lot of it, hadn't she?

"Beckett." Hmm, that was her name. It sounded nice when Castle said it like that, all rumbly and right up against her lips. She pressed her mouth to his again, and "Beckett" he said again. Why? Why was he saying her name instead of kissing? "Beckett."

"What?" she asked impatiently.

"I crushed it. I'm sorry."

She had to pull back to get her eyes to focus on his face. She had no idea what he was talking about. What? "What?"

"The mistletoe." He looked so sad, she just wanted to kiss him and make it better, but when she tried, he turned his face away. "I crushed the mistletoe, Beckett. It's, it's gone."

He pushed her away, gently, and looked down. She looked down too, and there it was, the sad little piece of mistletoe on the floor, smashed to pulp by Castle's shoe.

"Oh."

"Can't kiss you any more," Castle said sorrowfully. Beckett blinked up at him. Her lips felt swollen and tingly from the kissing they had already done. She certainly wasn't ready to stop, now that they had started.

"I have something else to show you, Castle," she said huskily. Oh, desire and alcohol certainly made her voice sound sultry, didn't they? And Castle liked it. Judging from the way his eyes darkened, he liked it a lot.

"What is it?" he asked, swaying a little on his feet, his shoulder bumping hers. His hand was on her arm, hot and electric through the fabric of her blouse.

"Look. More mistletoe," she grinned, and she brought her hands to the button of her work pants. She popped the button, pulled down the zipper, and let the pants fall open.

The panties had been a gag gift from Lanie a few Christmases ago: the first Christmas after Castle started shadowing Beckett, in fact. Lanie's intention had been clear, but Beckett had scowled and shoved the offending item to the very back of her underwear drawer. She hadn't thought she would ever have a need for white cotton boyshorts with a picture of mistletoe and the words "Kiss Me" right over the crotch.

Well, she had been wrong about a whole lot of things since Castle came into her life.

She pushed her pants down low on her hips so that Castle could see. She pushed them a little too far, though, and the pants fell to her ankles and she swayed, almost losing her balance, grabbing Castle's arms to steady herself. His hand came automatically to her waist to anchor her, and she gasped when his fingers met her bare skin.

"Beckett," he breathed, staring down at the panties. The green mistletoe, the red words. "Kiss Me!" they said.

"Kiss me!" she said. She grabbed his ears with clumsy hands and pulled his mouth down to hers again.

Oh yes. This was good. Kissing Castle. Not pretend drunk. Not pretend kissing. She licked her way across his lips and inside, but then he was pulling her away again. His hands on her shoulders, steering her to the couch. He pushed and she lost her balance and fell on her butt on the couch, bouncing slightly. Good couch. Nice and bouncy.

Oh. Castle was on his knees, pulling her pants off her ankles. "Beckett. Beckett."

"Castle," she said back, and she tried to lean down to kiss him some more, but he was too far away and her muscles wouldn't work properly to pull her forward. "More kissing," she whined.

"But the mistletoe," he said. "I'm supposed to kiss under it." His fingers traced the outline of the mistletoe design on the panties, and she gasped, her hips jerking under his touch.

"Oh shit," she heard her voice say. "Oh God, Castle."

"Is this - can I? Do you want?" he said, his words all jumbled. He leaned forward and pressed his mouth to the mistletoe picture. She moaned loudly. "Beckett," he said. "Do you?"

"Yes, oh God yes. Kiss me," she gasped brokenly, and he pressed her knees farther apart and moved his mouth farther down, kissing the panties again in just the right spot, and her hips lifted off the couch, pressing against him urgently.

"Under the mistletoe," he said blurrily, and pushed the panties to one side, and kissed her bare flesh. She moaned again, clutching at his hair.

Dimly, at the back of Beckett's mind, something was trying to tell her that they shouldn't do this, but she couldn't concentrate on it. Not with Castle's tongue sliding through her core, and the deep noises of pleasure he was making, which vibrated deliciously against her. She was making noises of her own, whimpering and gasping for air as he tugged her hips farther forward on the couch and pressed his face into her. All conscious thought left her brain when he began to suckle, and her eyes slammed shut and everything burst apart in a flood of white heat.

She didn't know how long she lay there, floating in the haze of ecstasy, but suddenly the couch dropped out from under her and she gasped dizzily, clutching at Castle's shoulders. Oh, he had picked her up. Somehow her blouse and bra were gone, and she was naked, and Castle was in a t-shirt and boxers, carrying her.

She was still panting and her muscles felt like jelly from the alcohol and the blinding orgasm, so she could only manage to push weakly at his chest. "Castle, put me down. You're drunk."

"You're drunk," he contradicted, weaving across the floor toward the hallway that led to her bedroom.

"Am not," she protested, struggling to keep her eyes open. Her head drooped against his shoulder. She wasn't drunk, she told herself. Just tired. "Jus' tired," she slurred. "If you drop me I swear I'll-"

"Bed," he said, and dropped her onto it. Oh. Bed. Yes. She reached for him...

Beckett sat up on the bed, groaning. That was all she could remember from last night. "Oh god, Castle, what did we do?" She looked over at him and found him staring at her with a strange gleam in his eye. "Castle! Don't look at me when I'm naked!"

"I think it's too late for that, Beckett." He sat up next to her, the cuffs jingling between them. "How much do you remember?"

"Um." Oh God. She couldn't - couldn't say those things, the things they had done. "Those damn panties! I'm going to kill Lanie."

Castle grinned, even as his cheeks turned a little pink. "I liked the panties. A lot."

"Shut up," she said nervously, inching away from him. "Castle, why the handcuffs? I don't remember that part."

"Oh." He ducked his head, looking up at her. "I, uh. I didn't want to. Um. I didn't want our first time to be like that. Drunk."

She blinked blearily at him. Her eyelids felt like sandpaper, her head was still pounding, but now her heart was racing also. The nearness of Castle was definitely getting to her, and his words. Our first time.

"Castle. Do you mean we didn't...?"

"No. Oh, no, Beckett," he said earnestly. "After I carried you in here, I just wanted to lie down and rest. But you said you didn't, didn't-" he faltered briefly and finished in a rush, "want me to get away, so you got out the cuffs."

"I cuffed us together?" she said skeptically. But now that he said it, memory was slowly seeping back. Maybe she had done that, in fact. To ... to keep him here?

"Beckett," he said, and suddenly he was kissing her again, morning breath and all. She let out a needy little noise from the back of her throat, and gripped his head with her free hand, kissing him back, even as all the alarm bells began to clang, reminding her again and again of all the reasons not to. All the reasons why she had been holding Castle at arm's length. Oh shit, he was well within arm's length now, and oh shit, speaking of arms, his hands were - and she was naked-

"Castle," she moaned desperately, and he pushed her down on her back and covered her body with his, kissing her again.

"Who needs mistletoe," he mumbled against her cheek, trailing his mouth down her neck. She gasped and tried to lift her other hand to his shoulder, but the cuff bit into her flesh because he was trying to slide his own hand across her hip. She yelped at the pinch and he startled, lifting off her.

"The key, Beckett, where's the key?"

"Oh god," she groaned, and let her head flop back onto the pillow, concentrating on breathing slowly and evenly through the raging storm of lust, trying to think about the key. "Purse," she finally decided, "in my purse."

Getting up from the bed was awkward with their hands cuffed, but once they were up, they moved together with surprising ease. Or maybe not so surprising; they had experience, after all. Recent experience.

"Sure there's no tiger in your living room?" Castle asked into her neck, and she shivered, pulling her robe around her shoulders as best she could with one hand.

"Very sure, Castle." She took another steadying breath. "And could you not talk so loudly? My head is killing me."

"Sorry," he whispered.

In the living room, she found her purse on the floor and they sat on the couch while she dug through it for the key. When the cuffs fell open and away, they both sighed a little, and then paused, staring at each other.

"Beckett," he began, but she shook her head quickly, raising her hand to silence him.

His eyes were wide as she stood up, and when her hands went to the robe, instead of pulling it all the way on, she let it fall to the floor.

She knew they should be talking about this. But call it the lingering aftereffects of the wine, the mistletoe, the fuzzy pre-caffeine morning brain, or whatever it might be - she just wanted him, now. Right now.

"Come on, Castle," she said hoarsely, taking his hand to pull him to his feet. "We're all out of mistletoe, but I still have a present for you."