I have no idea if this actually counts as an M, but I'm putting it as it just in case.

I love the way you love my books

The card is stuck inside her favourite coffee mug one morning, and she pulls it out as she shuffles from the shelf to the stove, the hem of Castle's shirt tickling the backs of her thighs. She turns the card over in her fingers, mulling over the words he's written around the frame for the Jack of Spades.

"Castle?"

He appears at the door, sleep rumpled and dressed in nothing but his boxers and raises an eyebrow at her. "Hm?"

"You love the way I love your books?" He smirks in that self-satisfied way he has when he knows he's got something that he can hold against her, and she narrows her eyes at him. "Castle."

He stepped up behind her, pinning her to the side of the stove and she can feel the heat of his chest through the thin cotton of the shirt. "Yesterday… when I came in…"

"You were crashing about in here…" Kate murmured, running her finger across the edge of the card. "And when I asked you why you were crashing about in here you were very secretive."

"Only because you were… busy… doing something else." He nibbled on the column of her neck, his hips pressing incessantly pressing into hers. "And I didn't want to interrupt."

Kate attempts to turn around but he stops her, laughs at her attempt of moving so she could get at him. "Do you know how hot it is when you walk into your girlfriends apartment and she's been lying on her bed wearing nothing but a pair of ridiculous barely supposed to be there underwear and a t-shirt, and she is attempting to read your book but she's so ridiculously turned on she can't concentrate? So… she slips a hand into that barely there lace – and she's so wet, she is oh so wet – and she carries on reading."

Castle pulls the card from Kate's grasp – smoothing out the wrinkles from where she's been bending it with her grip and leaves it flat on the surface. Kate is still beneath him, her muscles tense and her breath hard and uneven. He pushes closer, his own need becoming more present against her.

"But then… things get intense and suddenly just a hand isn't good enough. Then it's a finger, but that's not good enough. That's never good enough because she's been spoilt, so she adds another, long and slim and absolutely dripping, and it's so much better and all she needs now is to press the palm of her hand just there and twist her hips like that-"

Kate turns around viciously – hands flat against his chest – and glares at him. And he would be scared – he would – but her eyes hold more arousal than anger (and oh, he does like it when she's aroused and angry all at the same time).

"You know about that."

Castle stepped back, leaving Kate pinned against the stove feeling cold and definitely not anywhere near being satisfied. "No, I didn't, I just guessed. But it's nice to know that you get off while reading my books.

Kate growled and pushed herself back against him. "Castle."

"Well, you did make it obvious. Your cheeks were that delightful shade of pink, and you dragged me belt first back into the bedroom as soon as you saw me. You wanted something, and I was the only one who could give it you. But I wasn't there, and the next best thing was my books."

Kate hummed against his neck, curled her hands against his back. "Maybe I just wanted to get off to your books. Maybe… I just wanted to read Nikki and Rook, imagining how you'd sit at your desk writing and imagining that it's us." Kate leant back, the movement pushing her hips into his, making his eyes flutter. "Cos you did, didn't you? Every single time they fucked, or made love, hard and fast against her front door, or long and slow in bed. It was never them. It was always us."

Later he'd deny that he whined, but Kate knows what she heard (recognises it from the number of impatient whines that he's drawn out of her), scrapes her teeth across his stubble just so she can make him growl. And Kate does like it when he growls.

"We haven't done the front door in a while…" he muses, his hands finding purchase against her hip. "And you're not wearing any underwear."

"You're wearing enough underwear for the both of us."

"Hard to do anything against anything with underwear. You wanna change that?"