Work Header

Genetic Markers

Chapter Text

Rain pattered down in the windows as Mary whispered softly, “Let's bring it up to him tonight. I want to get started.”

“Impatient,” John murmured, kissing her neck.

“Not getting any younger,” she reminded him, sing-song. "Tick-tock."

The little one was probably nearly down for the night now. From the babyroom came soft pacing footfalls and a very pianissimo rendition of “Twinkle Twinkle Little Star” for solo violin. How the haughty had fallen. Soon the last note would die away, and the flat would fall silent as everyone waited for the consent of a baby's sleep. The monitor would crackle softly – for all they knew, someone in MI6 was on it – and then Sherlock would pad quietly into the bedroom in his robe (which one was he wearing tonight? John liked the blue, but Mary loved the red) and nearly always stand there a moment at the foot of the big bed, with a heart-shaking diffidence.

He might watch for a while, drink in Mary's quiet moans as John nibbled at her breasts and lifted her nightgown; he might smile in that lusty way if he was feeling sure he'd be invited. (And after all this time, how could he doubt? He always would be; he would always crawl in eagerly and tangle with both of them wantonly in a three-way circuit that sparked longer and brighter and wilder than any dual connection any of them had ever known.)

“We could just let him deduce it,” John said wickedly into the top curve of her right breast as he slid his hand down her hip, just brushing an old mass of puckered, damaged skin. (There was no one in this marriage without a bullet scar. Maybe that even made it easier to forgive the fact that one party to the relationship had given another one his; look at it as an initiation or a sort of wedding token. Sherlock might even be able to do that. John couldn't quite.)

“It's not his strong point, though, is it?” she said, turning and squirming around beneath John.

“He knew you were pregnant before you did.”

“Not completely sure he knew how it was done, though.”

John snickered. “Didn't hear you complaining about his technique the other night.”

“Oh, he's certainly learned by now. Very well.”

“Just tell him he still needs practice in . . . that. Just that.”

“So you -” Mary said, laughing, running fingers down John's chest to pluck at his sensitive nipple, “out of the goodness of your heart, are going to willingly exile yourself from my gates of heaven for as long as it takes - ”

“Oh god, please,” John giggled, snorting,

“While we insist that the other man in our marriage plough my valley as often as possible, for Queen and country - ” Mary's hand was sliding down his belly, running teasing fingertips down the top of his heatening shaft - “and it's all because he needs practice.”

“That's right,” John said breathlessly as she stroked him and he moved his hand up her thigh to his lodestar, unable to keep his fingers out of the debated territory, wet and swelling as it was, “not at all because we want another child -”

“And were - oh, fuck, John, yeah – afraid he was feeling left out with the first one already - ”

“Oh yeah Mary, fuck, slow down, that just feels too good – yeah, he needs to know he's really with us . . . forever . . . all the way . . . and it'd be a shame to let genes like that go to waste –“

“And it's not like - ” Mary panted, pushing John's head down between her thighs, “he hasn't been listening to everything we said.”

“I have been, but I'd really like to be sure I've heard everything correctly to make sure I've come to the right conclusion,” said Sherlock, popping out of the shadows like a spook. “Because my current interpretation is bizarre even by our standards.”

Mary gave a heated little mewl as John began to lick deftly at her clit; he was clearly hoping to find an excuse to contribute little to the negotiation. “What's so bizarre about – ooh – wanting another baby? Nothing wrong with having two!”

“Of course not, but an outside observer listening in -” (and Mary could not help but notice Sherlock still kept a safe distance from the big bed. Oh, that just couldn't stand.) “would probably interpret it to mean that John was planning to abstain from vaginal intercourse with you, and to encourage me to partake of it frequently, in the hopes that I would be the one to impregnate you.”

'GOD, you're thick,” Mary said, with a little squeal as John's tongue picked up pace and her hand clenched in his hair. “It's the only way it's going to work, isn't it? Believe me, if someone else in this marriage could get knocked up instead of me I'd be all for that!”

“Someone else . . . in this marriage,” Sherlock said, weighing the phrase in a contemplative tone of voice, as though he hadn't quite thought of it that way before with quite the same quality of weight. “I hadn't . . . ” He went still and silent.

“Did I just break your brain? John, is that it what it looks like?”

“Can't talk. Busy,” John slurped.

Mary sighed and winked at Sherlock. “That's our husband. A man of action.”

“Yes,” Sherlock said finally. “John is certainly that.” He was fidgeting, and that robe – the red one – seemed about to slide from his shoulders of its own will, and his thin pyjamas were only accentuating his interest in the action before him and the indecent proposal.

“So what do you say? I think I'm ovulating – OH GOD, OH JOHN, MMMMYESNONOTYET YES. Hormones off the scale, it's awful, I'm a cat in heat. Will you just come here and fuck me, and then maybe John can fuck you, and -”

John nodded so emphatically that he moved his tongue just so that Mary did come. Just a little one, just one sharp yelp and a few shaking twitches that derailed her train of thought for just a moment. Then she was fine and right again and ready for many more.

“See, Sherlock? He wants to, he wants to so bad, and so do I, and haven't you ever thought about it?”

“I'd never thought about it before tonight,” Sherlock admitted, and he was smiling now. There was a probably a new room forming in the mind palace, and only he knew what it looked like. And whether or not there was a cradle in it. “But I've thought about it more in the last eight seconds than most people think about anything in a year.”

“So?” Mary said hopefully. “Is the game on?”

Sherlock's eyes narrowed calculatingly. “You do understand, I'll be very interested in studying the minute daily changes in your cervical mucus as we go through the conception process.”

John groaned. “That's nice. I'm really fucking horny over here. Can you fuck first and take samples later?”

“I do understand the basic order of things, John,” Sherlock said, shucking off the last of his clothes and pouncing hungrily into Mary's arms. She was soaking wet, he was throbbing hard, and the sight and sounds and scents of their vigorous coupling almost got John off without a touch.

John knew he'd be compensated well for his minor sacrifice, though – he was the luckiest man on earth, after all – just a little while later he'd be thrusting into his gorgeous husband's lazy, pliant body while his gorgeous wife did her best to keep her lubed fingers in his hole and her kissing, biting mouth on his nape. Between the three of them, there were at least a dozen possible sexual acts he enjoyed very much, and only one he'd have to forgo until it was confirmed that Mary's remarkable fertility had done its work, which shouldn't take long.

It wasn't until the sleepy haze of the next morning that John remembered to look forward to meeting a new person, hopefully within a year. A sweet face and precocious interest in blood-spatter patterns? Dark curls, and a violin-playing insomniac by age 5? And would he see a few more glimpses of the child Mary had been, knowledge that was forever lost?

Over breakfast while feeding little Violet in her high-chair, Mary had threatened to “have a chat with Mrs. Holmes about pushing out the cheekbones.” Sherlock had made that particular eyebrow raise that meant something like, “I cannot prevent Mycroft from making you disappear, if it comes to that,” and she had laughed like a clear stream of water.