The Christmas after Rosie turned five years old was a busy one in the Holmes household.
Violet Holmes had insisted John and Mary needed to stay at the house for a few days so she could have her time with Rosie, whom she didn't get to see nearly as often as she'd like. Then Mycroft had gone and gotten himself engaged to a high-ranking CIA official by the name of Naomi, and Molly had let it slip that she had no plans that year save to stay at home with her new cat, and the whole thing had spiraled right out of everyone's control.
Sherlock had gotten a call from his mother a week before Christmas day, informing him that if he didn't bring that pretty redhead she knew he was living with, she'd turn absolutely monstrous. Which was how they'd wound up in a house with eight other people and too much food and too much noise, and very little room for privacy.
The problem was they'd been too late.
Sherlock had a case to close and Natasha had a debriefing to get through, and by the time they'd arrived on Christmas Eve, John and Mary had settled into one of the guest rooms with Rosie, Mycroft and Naomi had settled into his childhood bedroom, and Violet had deemed it fit to give Sherlock's to Molly so she'd be comfortable.
Which left Sherlock and Natasha with the fold out couch in the living room, that also doubled as a bed. It was comfortable, of course, and they weren't exactly prudish when it came to physical affection, as anyone who'd witnessed them snogging on the stairs of 221b would be happy to testify, but there was a child in the house and they had to be careful.
Or so they'd been told by John, with a pointed look.
After a large dinner and hot chocolates by the fire, they'd finally snuck up to the little library Mycroft and Sherlock had built up during their younger years up in the attic, only to find that it was otherwise occupied. Mycroft had poked his head out with his clothes all crumpled and his cheeks flushed and advised them to find other accommodations while Naomi giggled quietly in the background.
Natasha heaved an exasperated sigh as the attic door closed on them again, leaning back against Sherlock's chest. He snaked an arm around her waist and brushed a kiss to her neck, nipping gently at her skin. "I'd suggest using their bedroom, but it's right next door to John and Mary's, and the walls are thinner than you'd imagine," he said quietly. "Mycroft's snoring always filtered clean through, barely let me sleep for a decade.
Another round of giggles came from the other side of the attic door and they both glared at it in contempt. Between Sherlock's case and Natasha's mission abroad, they hadn't had time for so much as a snog in a week and a half, let alone anything else.
They'd been hoping for some alone time over the holidays, but with every passing second it was looking more and more like they wouldn't be getting it anytime soon.
Then Natasha all but jumped in Sherlock's arms, whirled around to face him, and drew him into a deep, smoldering kiss. He moaned in protest when she pulled away. "I have an idea," she breathed out, all bright green eyes and mischievous smile. She grabbed his hand and tugged him down the stairs. "Come on."
Some fifteen minutes later, they'd stolen Mycroft's keys from his dresser, snagged a blanket from the linen closet, and parked the sleek black Jaguar in an open field near the house. Outside it was freezing cold, but they'd blasted the heat while they'd been driving around searching for a decent spot, and inside it was toasty and warm.
Sherlock killed the engine, and Natasha straddled his lap as soon as they were settled in the back seat. She was smiling and her cheeks were pink, and he pushed her skirt up until it bunched around her hips, leaving her thighs bare to his touch. There were no words. Natasha leaned in to kiss him slow and deep and greedy, and his hands trailed over her hips, up her sides and underneath her sweater until they found the thin lace of her bra.
She tucked her hand in his hair, moaning softly into the kiss. "Missed you," she said.
"Want you," he rumbled back, biting at her bottom lip. She nipped him in return, and he pulled away just far enough to yank her sweater off her. The thing tangled in her earrings, and he kissed a giggle from her lips when they finally managed to snag it free. Slow and sweet at first, Sherlock cast the sweater aside to rake his fingers through her hair.
Natasha rose up on his lap to kiss him deeper. "Need you," she breathed in Russian. "Now."
Sherlock's fingers all but flew down his shirt buttons, tugging the hem free from his trousers while she popped them open with nimble fingers. He grasped her thighs in large hands when she finished, dragging her closer, sliding his fingers underneath her skirt.
There was nothing else, only the two of them in the that seat, all flushed skin, ragged breaths, moving together until their breaths turned quick and erratic, and the windows fogged over from the heat of them inside the car.
When they finally stilled in each other's arms, breathless and sated and dizzy from the natural high, Sherlock pressed his forehead to Natasha's neck, panting against her collarbone. "Ya lyublyu tebya," he breathed.
"Ya tozhe tebya lyublyu," she panted back, brushing a kiss to his temple and carding her fingers through his sweat-damp curls.
He reached blindly for the blanket they'd brought with them and wrapped it around her shoulders as she slid off his lap, smiling and satisfied and thoroughly loved on. She tucked herself against his side, and their eyes met for a silent beat.
They both burst out in a breathless laugh.
"Mycroft might very well kill us for this," she said.
"Yes, but it was your idea," he pointed out. He had that rare smile on his face, though, the one that made his eyes go all soft, just for her. He tugged a bit of the blanket over so they were both covered, and wrapped an arm around her shoulders. "Though admittedly, I didn't protest."
"Stole the keys and drove the car, actually," she deadpanned.
He pressed a kiss to her forehead, then another to the pink tip of her nose. "Extenuating circumstances," he said.
She let out a soft laugh. "Sounds reasonable to me." Sherlock ran his fingers through her hair in the silence that followed, and she closed her eyes to focus on his breathing. "Thank you for inviting me, by the way."
"I was bullied into coming here by my mother," he spoke against her temple. "And Mycroft."
Natasha smiled to herself. "Still, though. It's my first real Christmas."
Sherlock's hand stilled briefly in her hair. He peeked down at her. "What about last year?"
"We were working last year," she said. "Technically, anyway."
He resumed his gentle ministrations, winding and unwinding strands of hair around his fingers the way he so frequently did. He was quiet another long while before he said, in that same hushed voice, "What about before?"
She shrugged a shoulder. "If I celebrated any, I can't remember now." She tipped her head back on his shoulder to meet his eyes. "Maybe one day, I do get snippets every once in a while."
He furrowed his brows and she reached over to smooth it out. "It's a good thing," she promised. "And the fact that I get to remember spending my very first Christmas with you and your family more than makes up for it."
"Our family," he corrected quietly. "My parents are very taken with you already, you can't have missed that."
"You think so?"
"I did say it, didn't I? Pretty sure that was me."
Natasha pulled him in for a kiss on the lips, gripping an open half of his shirt. "What are we going to do about that mouth of yours," she sighed as they broke away.
"Mm, I have several ideas, actually." He brushed her nose with his, smiling like the cheeky bastard he was. "I could tell you, but it's always so much more fun to demonstrate."
She exhaled a quiet laugh. "Incorrigible."
Sherlock's laugh rumbled low in his chest in that way that made her heart do all kinds of flips and flutters in her chest. He cradled the back of her head and nuzzled her again. "Merry Christmas, Natalia."
She closed her eyes and breathed him in. "Merry Christmas, lyubimiy."
Hours later, Violet Holmes would walk through the house, tidying up Rosie's shoes and Molly's sweater and Sherlock's Belstaff thrown over the back of the couch. She'd hear a laugh drift from Mycroft's room, a quiet 'I love you' from John and Mary's, and she'd round the corner just in time to see Sherlock and Natasha sneaking back into the house with their clothes all in disarray. She'd smile to herself and bustle back up the stairs, thinking maybe, just maybe, her boys were finally in good hands after all.