A/N: Set post 5x01.
Kate finds him appraising himself in the mirror as she pads towards the bathroom, the darkness of night shrouding her from view. She quirks an eyebrow while he sucks in a breath, presses his palm to his stomach and pokes at the softer edge of his side.
"Castle?" she chuckles, raspy and still quiet with leftover slumber, earning the swivel of his gaze to the mirror, the sheepish twitch of his lips and cross of his arms over his midsection. Embarrassed.
"Hey, thought you were still asleep."
"I was. I had to pee."
A laugh flutters out of him and Kate steps into the bathroom, steps up behind him and splays her hands just below his pectoral muscles.
"Checking yourself out?"
She swears his cheeks turn pink.
"No, just... examining. I should probably dedicate at least a portion of this summer to fitness, huh? I've been slacking."
"Mm, I haven't been able to tell. You've got excellent stamina," she mumbles, her mouth feathering along the back of his shoulder and tugging a grin to his lips that she echoes against his skin.
"But I'm not - I'm..." His hands come up again, pinching at his waistline. "Squishy."
"Rick," she huffs, refraining from laughter because he's quite obviously distressed to some degree over the insecurity that she doesn't quite understand.
So she slides her hands down to his abdomen, slips her fingers beneath the offending digits of his own that pluck at his flesh and spreads them wide, soaks the warmth of his skin into her palms.
"You're not squishy."
"But I'm not chiseled."
Her brow furrows at that and she shoots him a questioning look in the mirror. "So?"
"Well, I just know you're attracted to-"
"Castle," she chastises on a murmur, retreating from his back to slide between him and the sink that brackets the mirror, stretching on her toes to block his view. "Are you seriously questioning my attraction to you?"
"No, not… I just - I'm not your type, necessarily?" he shrugs, his adam's apple bobbing with a nervous swallow. "I mean, every boyfriend you've had since I've known you has been physically fit and muscular, and Colin Hunt was-"
"I didn't want Colin Hunt," she argues, twining her arms around his neck and appreciating the broad wall of his chest beneath hers, the heat of his skin and the expansion of his ribs as he breathes. "I wanted you."
She appreciates the way he shudders beneath her too.
"Even... even then?" he murmurs, his eyes mercurial in the dimness of his bathroom in the middle of the night, curious and uncertain, and she sighs.
His hands frame her waist, his palms so broad and encompassing and warm, reminding her just how much she loves his hands, how many times she imagined them on her body long before the idea every became a reality.
"And I admit I may have had a type that I tended to gravitate towards, but I don't feel like it was ever a secret that I was attracted to you," she adds, but Castle doesn't look convinced, draws his hands up and down her sides before he settles his fingers to curl at her hips. Never did she think the supposed playboy with the massive ego would need reassurance over something like this, let alone from her, but she doesn't mind giving it, is determined to ensure it. "Rick, stop it. What if I was comparing myself to every other woman you've ever-"
"There's no comparison," he states immediately, his eyes so serious and blue, his hands flexing around her hips, and Kate undulates against him.
"I feel the same way about you," she murmurs, promises, because it's true. He may not have every muscle chiseled and sharp, may not meet his own standards, but she adored his body, every inch of him, and she wants him to know. Needs him to know.
"Kate," he breathes as her fingers trickle down his chest, tracing over the hard lines of his chest, following the lattice of his ribs down to his abdomen, teasing along the waistband of his boxers.
"I love your body," she husks, her voice brimming with arousal that has bloomed of its own accord. "It's only been a few weeks, but I've explored you pretty thoroughly so far, Castle. And not once have I been disappointed."
He cants forward when her knees so naturally embrace his thigh between her legs. She's in one of his t-shirts, nothing underneath, and she bites her bottom lip to suppress the smirk when he notices, feels the proof of just how attracted she is to him stain his upper thigh.
"I've never been disappointed," she mumbles even as he groans, presses in closer, drags her higher up his thigh. "Even before I got to see you naked."
He hums, an agreement she can't hear when he mutters it against her neck while his fingers toy with the hem of his shirt. She lets him touch her for a moment, brand her skin with seeking hands up and down her sides, and then she coils her fingers at his ear, gently draws him back so she can see the midnight blue of his eyes.
"I like how you're firm in most places, but you're soft too," she continues, watching intrigue and a bit of wariness infiltrate the electricity jolting like a circuit around his pupils.
Kate drags her fingers to the strip of flesh just below his hipbone, fitting her hand between them to stroke the sensitive skin there and hear the sharp breath he sucks in. "Here."
"Where else?" he chokes out, his entire body beginning to thrum with need against hers.
"Here," she murmurs, trailing her hand up the length of his arm, touching two fingertips to the inside of his elbow. Castle's head tilts back slightly when she nudges her nose to his chin, opens her mouth over the tender skin beneath. "Here too."
His eyes fall closed as she brushes a kiss there, quests along his jaw to find his ear, take the lobe between her teeth.
Castle's hand slides into her hair, tangling in the strands as he coaxes her to ease back so he can press his mouth to hers, stroke his tongue past the seam of her lips, and sear her with the intensity of his kiss. Her body instinctively arches, a moan building in her throat as she seeks more, glides one of her hands down the hard muscles of his back, the curve of his spine bowed over her, and slips her fingers past the waistband of his boxers.
He thrusts at the squeeze of her hand, the dig of her nails, and gasps for breath against her mouth.
"I love this body, how it fits with mine," she breathes, smirking when grins and coasts his hands down her back, hooks his thumbs in the edge of the shirt and tugs it back up her body.
"Don't start quoting E.E Cummings at me, Beckett."
"I was tempted," she muses, humming when he seals off her laughter with a kiss that is less hungry, more tender, grateful.
The shirt slips over her head and she doesn't hesitate in crushing her chest against his, feeling every stretch of smooth skin beneath her own, every beat of his frenzied heart vibrating through his flesh, transferring to hers. Kate rises on her toes, wanting to feel more and using the support of his arms around her to hook her knee at his hip, fitting the pieces of them together and giving him the excuse to carry her to bed.
Castle hoists her onto the edge of the sink, sweeps his hands along her breasts, travels over the planes and valleys of her upper body until she's panting into his mouth, rocking into his hips.
"Castle," she gasps, groaning in relief when his hands cup her ass, his grip on her secure like the legs tangled around his waist.
They stumble into the bed when she grows impatient, dragging him down on top of her so she can arch beneath him, relish in the solid weight of him anchoring her to the moment. But Castle is abandoning the perfect merge of their bodies, his mouth meandering down her throat to her chest, venturing downwards to her abdomen, her – oh, she can't help moaning when his mouth finds home between her legs.
"Rick, please," she mewls, part of her surprised by how quickly he's managed to take control of the situation, how swiftly it went from her reassuring him of her adoration for his physique to him undoing her from head to toe. "I wanted – want you inside, want to feel you."
His breath shudders out against the strip of skin beneath her navel and for a second, he rises above her, layers his body over hers and lets her feel every part of him once more.
"You love my body," he mumbles, his lips glancing her cheekbone, the corner of her mouth, her teeth just shy of catching his bottom lip as she nods. "Let me show you all the ways I love yours, Kate."