"There's no way," Mary says, rolling her eyes at Sherlock. "First off, you wouldn't."

"Who says?" Sherlock asks indignantly.

Mary laughs softly. "Fine, then there's no way you'd be able to when it comes to John."

"I'm quite keen on the art of seduction," Sherlock replies with a shrug, handing Mary a tea and taking a seat in John's chair across from her space on the sofa.

"I will bet you that you can't," Mary says, cradling her young child in her arms.

Sherlock shakes his head. "You don't want to challenge me, Mrs. Watson. You know how I am when a game is struck. Additionally, there is nothing you could offer me in a bet that would make it worth John feeling uncomfortable in a promiscuous situation where he could feel guilty for cheating on you."

"Firstly, I give my full permission so no guilt needed," Mary replies with a shrug. Sherlock's face contorts with shock. "What, I get bored too. And as for the wager…slap bet."

"What?" Sherlock asks, curious as to the new concept.

Mary shrugs. "I saw it on an American show. The winner of the wager gets to slap the other person in the face."

"Amenable," Sherlock replies as he puts his tea aside to clasp his hands together. "Who says I want to?"

"It's quite obvious, dear," Mary says with a wink. "I'm handing you an opportunity, take it. Well, if you can, which I still doubt."

Sherlock bounces from John's chair and moves over to Mary, shaking her hand. "Deal."

John walks in while they are shaking hands. "What is it this time?"

"Nothing of importance," Sherlock brushes off as he walks up to John, smiling his smile he only uses to charm customers. "How are you today?"

"Why is he acting odd?" John leans past Sherlock to ask Mary before moving over to the couch to take baby Sheryl (the winning of a very different wager/argument's production of naming) into his arms with a great big smile.

All Sherlock can think is the game is on.

Sherlock figures out quickly that acting charming around John will do no good. He tries another method. "John, I'm bored," Sherlock says as he pounces down in his chair a few days after, pulling a new strategy.

"Well, I'm busy," John says. Sherlock sighs and gets up, following John around the flat. "You following me around like a lost puppy isn't going to help any."

"Let's go play murder," Sherlock asks, smiling brightly.

John shakes his head. "You know you're not allowed after the Magnusson case, Sherlock, now go shoot the wall or something." Sherlock's eyes light up, he may have gotten distracted for a second. "No, Sherlock, don't actually shoot the wall again."

"What do you suggest?" Sherlock asks, leaning on the counter in front of John, blocking him from getting his tea.

John can think of a thousand things Sherlock could be doing other than distracting him. His words though, as he looks the detective up and down in front of him, don't reflect that. "I…uh, I don't even know, Sherlock. You are a grown man, figure it out."

Sherlock reaches up and ruffles his hair. "Fine, you're boring."

"I'm not boring, you're on house arrest," John yells back in response as Sherlock descends into his room.

Sherlock comes back out a few minutes later wearing nothing but a sheet again. It's far more comfortable for him, and for the game's purposes it's always been an apparel choice that's caught John's attention. Sherlock slumps on the couch, letting the sheet drift so it just barely covers anything.

John walks into the living room and his eyes go wide. "Well, you're not wearing any pants."

"Shut up," Sherlock replies, falling into his own head.

John shakes his head, walking up to the couch and poking Sherlock on the shoulder. "If you want to be half-naked and ridiculous go do it in your room."

"Feel free to join me," Sherlock says under his breath as he gets up and walks off, fully aware that he has let the sheet drop behind him this time.

John watches Sherlock walk away before he even notices he's doing it until Sherlock shuts his bedroom door behind him, leaving only a crack open with John's invitation left clear. John shakes it off, thinking he must have misheard Sherlock.

It takes exactly five minutes before John can't take the uncertainty anymore and knocks on the side of Sherlock's door. "Did you really say what I think you just said?"

"I might have," Sherlock replies in a lower register than usual, doing some things in John's brain that he wouldn't like particularly to admit at that moment it did.

"I'm straight, I'm bloody married Sherlock," John says as he peeks his head in the door.

Sherlock smiles brightly as John steps inside. "Then why are you here, walking in further and further with every word, knowing full-well my intentions?"

John shakes his head, walking in the other direction. "Weird."

Sherlock groans, flopping his head back on his bed, wondering what he could do that could entice John. He gets dressed. A few days later another idea sparks. "John!"

"What, Sherlock?" John asks, wondering as a part as to why that's the first word Sherlock's said to him to what he would refer to as 'the awkward incident' if he chose to let it bother him, which it didn't.

"Can we do an experiment?" Sherlock asks, rocking back on his heels as he skids to a halt in front of John.

"Not like what I'm sure the other day was?" John asks tentatively, taking a deep sigh of relief as the explanation presented itself.

Sherlock watches John for a few moments before nodding in aggreeance. "It's of a different nature. The nature in which you help me not feel stir-crazy and I help you not feel bored."

"I am not breaking you out of house arrest, Sherlock," John huffs as he walks past Sherlock, handing the detective a tea. "I will, however, help you research. Once this case is done, I'm sure house arrest will finish as follows."

Sherlock nods, walking over and sitting entirely too close to John for it to be normal. John jolts. "Okay, what is going on?"

"Nothing," Sherlock says in the most nonchalant nature he can manage in this lie. "I just thought research would be well-conducted together on your laptop."

"If you ever pulled out your own bloody laptop," John goes on rambling but Sherlock doesn't entirely listen as much as he just watches as John's lips move. Perhaps Mary was right, perhaps Sherlock wants this more than he bargained for initially. John notices after the third unanswered query that Sherlock isn't paying attention. "Sherlock, what is it?"

Sherlock shakes his head, focusing in on the third time that John's asked that question. "Nothing, like I said, we're on to research."

"We're not on to research," John replies, shutting his laptop and discarding it on his side. "You didn't hear a word I just said, did you?"

Sherlock looks at John for a minute before nodding. "I apologize."

"Can we talk about what's bothering you?" John asks hesitantly.

Sherlock is clear in the notion that he probably could've found a better response than the one that he exudes. He could have come up with something far more sophisticated, something much better than the blatant obvious reference to the information that comes next. "You don't want to know."

"Well, Sherlock, I may need to know," John replies, taking a deep breath before continuing. "I have one way to prove that your game is not going anywhere."

Sherlock raises his eyebrow. "I'd be lying if I said I'm not intrigued."

John leans over, and in an instant shock extends to fill the entire room as John is the one to make the first move towards them kissing. Sherlock moves forward to meet him halfway the second he understands what is happening, far more eager for the endeavor than he'd care to admit to. John feels more in it than expected, grasping the lanky detective around the waist and pulling him into his lap, shocked at the feelings running through him as Sherlock grinds his hips down into John's own.

Sherlock moans into John's lips before parting, opening and shutting his lips a few times before touching his lips and smiling. "What were you trying to prove?"

John blinks a few times before reality sets back in. "What, I, um…"

"The game is on," Sherlock says before leaning back in, pleased as John responds immediately, wrapping arms around his lanky body as Sherlock grinds their groins together through thin fabrics. Thin fabrics become non-existent layers as they peel away quickly and John finds himself positioning over Sherlock without thinking much of it.

"We need," John says, half-aware that he's asking for is what he's asking for between the clouds of lust.

Sherlock nods and reaches over the couch's edge to pull over his night coat and yank away a small tube. John finds himself laughing softly, as Sherlock was clearly more than prepared for this opportunity. John begins to slick up his fingers and inserts them digit by digit until there are three and Sherlock is bucking onto John's hand, begging for more pressure to his prostate (it was Sherlock, so it's not 'there, there again – the detective knows where the stimulation is coming from).

Sherlock yanks down John's face by the short blonde locks to kiss him again, a mess of teeth and tongue, before pleading with their lips still touching for John to penetrate him already. Sherlock's never felt these sensations before and they are all driving him to the brink of ecstasy far too quickly and he's not ready for this to be over yet.

John nods against Sherlock's forehead as he fumbles with the lid of the lube again. Sherlock snatches the bottle from John's clumsy hands and starts the process himself, slicking up his hand before starting to stroke John none too gently. John lets out a feral moan as Sherlock progresses with the stroking until Sherlock's lining up John's member with his entrance and a whole new level of pleasure is about to be accomplished.

John starts pushing in slowly before he feels Sherlock's long fingers dig into his bad shoulder. John looks up at Sherlock's face with confusion before seeing how flushed and concentrated Sherlock is, and it takes him seconds to recognize the pain on Sherlock's face. "I could, urm, I could pull out."

"Don't you dare," Sherlock warns in a lower, breathier register than usual. Sherlock hisses as John adjusts his body's position so that he can hover and wait comfortably for Sherlock to be ready whilst Sherlock is stuck with his legs up in the air around John's torso and awaiting adjustments.

"Sherlock, I really wouldn't mind-" John tries again after a few more minutes.

Sherlock shakes his head. "Distract me, John, the burn. It will feel more pleasurable soon, for the time being…"

"Alright," John whispers against the back of Sherlock's ear, earning a shudder that runs through the detective's entire body. Encouraged by that initial reaction, John delves down deeper, kissing up and down Sherlock's neck, feeling shock as Sherlock's mouth begins to make many obscene sounds that fall well with the trembling of his body.

It's when John turns to suckling at certain points that have come with the most gratified reactions from Sherlock that the detective begs for John to start thrusting, which he does after finally thrusting all the way in the first time. Once the first few thrusts are down, Sherlock starts moving more with John as they go. The thrusts increase in pace and the sounds that rip from each of them only serve to grow louder and louder. Sherlock comes first, heavy and hot spurts over their chests that didn't even require direct contact to be released. The contractions of Sherlock's entrance around John's member send the army doctor over the edge as well, feeling a sense of euphoria as he fills up his flatmate to the brim.

When it's all said and done, John assists Sherlock in lowering his legs and pulls out gently enough that neither of them feel too much of a shock from it. John can't find words for the first few minutes, Sherlock can. "She still wins."

"What?" John asks, not sure what Sherlock means at all. Better said, he hopes he doesn't understand what Sherlock is saying by that.

"Mary and I, we had a wager," Sherlock admits slowly as he sits up. "I was to see if I could seduce you, Mary bet that I couldn't so she gave her permission for anything to happen. In the case you were worried about the morality of our tryst I thought you should know there is no guilt within our actions."

John's face falls. "It was all just – you were hitting on me, it was just a game to you, Sherlock? Is that all I am?"

"No," Sherlock promises, plucking himself up to sit on his knees as he moves closer to John again, running his fingers through John's short blonde locks. "Never think that. The game simply gave me the opportunity to pursue you without consequence. However, you pursued me, so I lost. If that's at all comforting, I hope."

John leans into Sherlock's fingertips, enjoying even the simple caress. "I can't go back to being just flatmates, Sherlock. I'm definitely not fully straight."

"I could've told you that," Sherlock huffs, laughing softly as John elbows him in response. "You could leave the flat, find somewhere new. This is hardly a perfect place to start a family."

John shakes his head, moving his face over so that their foreheads can touch again. "How do I fare with losing something I never knew I wanted?"

Sherlock breathes deeply, not having the words to say but most certainly having enough actions as he reaches forward and kisses John one more passionate time.

Mary walks in at exactly the right moment, trying to fake being appalled at first before both men look at her with humility in humor. "It was worth a shot. I take it you boys had fun?"

"Plenty," Sherlock says, reaching onto the floor and yanking back on his pair of pajama pants before walking over to Mary. "I've lost the bet, you're husband seduced me instead. Smack me, then I'll be off packing."

Mary smacks Sherlock in the face, harder than expected. "You can't leave."

"I can't ruin a childhood and a marriage for my own emotions, I'm selfish but even I have my limits Mary," Sherlock replies as he goes to saunter off to his room.

Mary looks to John. "Why couldn't you have let him seduce you?"

John feels himself flush red. "I did, mostly, but then I went to prove a point that turned out false."

"He's not leaving. I don't care what you two do, as long as we all stay together everything will be fine," Mary promises as she runs after Sherlock into the detective's mess of a room. She runs in front of him and starts tearing things out of his suitcase. "You're not ruining my marriage. I've already ruined it, you see, because John can't love something he doesn't know."

Sherlock keeps packing his things away. "There is clearly enough strain on the relationship already. I don't need to be another obstacle."

Mary grabs Sherlock's arm. "You know if you leave it will break his heart."

Sherlock sucks in a few sharp breaths. "I'm trying to do the right thing."

"There's no right way to handle it," Mary promises, her iron grip on Sherlock's arm turning soft and comforting. "I'm not going anywhere and neither are you, no matter whether John loves me or loves you or us both."

Sherlock sighs indignantly, walking back out to John. "Question: what would happen if I were to leave?"

"I would come looking for you," John replies, his eyes fixing on Sherlock's. "I can't lose you again, Sherlock, I can't."

Sherlock smiles softly, climbing into his blogger's lap. "We're in quite the situation. Mary and I aren't at odds about it. It's whatever you want."

"I could be greedy if you give me the option to be," John whispers nervously.

Sherlock laughs softly. "I will too. I took up so much of your time before, how will it fare now?"

John laughs too, a smile lifting all the way to his eyes. "I love you." Sherlock stares at him blankly, as confusedly as he did when he was asked to be best man. John reaches up and kisses Sherlock softly, waiting for the detective to load. "Hey, you don't have to say it back."

Sherlock snaps out of it at the last verse and kisses John once again. "Of course the feeling is mutual."

John rolls his eyes. "That's not how people normally respond."

"I'm not a normal person," Sherlock promises with a wink before standing again. "Sorry, um," Sherlock doesn't know how to explain the discomfort sitting for too long at this point and just murmurs something about tea.

John chuckles, knowing the walk Sherlock gives to be lacking his usual grace. Mary walks over to him and he smiles apologetically. Mary laughs. "I actually do believe I set this up, don't be guilty. Sherlock's quite adorable. You'd think this was his first time or something."

John's eyes follow Sherlock nervously looking away, wincing at some movements. John leaps up from his seat and walks up behind Sherlock in the kitchen, snaking his arms around Sherlock's waist as the detective makes tea. "If I'd have known, I would have been a little more eloquent about it."

Sherlock shakes his head, leaning back into John's embrace. "Nonsense, you getting lost in a field of lust over me when trying to prove you didn't want me was quite priceless," Sherlock replies with a gentle smile. "Oh, and I love you too, John. I assume that's the customary response you were looking for."

"Yes, that'd be the one," John murmurs against Sherlock's back, laying his head comfortably as he holds tightly around Sherlock.

Sherlock turns around in John's arms, smiling like the madman he is. "Could we try again?"

"You're already walking quite bowlegged," John teases, earning a frown from Sherlock who readies himself to turn around, feeling bad for asking. John brings a hand up to Sherlock's arm. "What I meant is that, well, um…we could rotate. We could try at a time where my wife isn't one room over."

Mary shouts out something about not minding and being back later, waving to her boys as she goes to spend time with her little girl. She wonders just how they'd handle the life-changing wager – the wager to remember.