Oh, John is well aware how minimally Sherlock has interest in their love life.

At first, he was just grateful that Sherlock was letting him in. Sherlock is like a human fortress, all thick, large, heavy white bricks with chaotic patterns that somehow hold fast to create one of the strongest buildings known. He has walls that back up his walls, and he rarely lets himself be vulnerable to sunshine, let alone invasion.

But he let John in. And that meant something. Because Sherlock doesn't have to permit anyone behind his walls, not a soul. And yet John was allowed to see Sherlock's emotions, his naked body, his vulnerability. He opened himself up to John and took him into his arms. And John was content to be there, to have Sherlock, to keep him.

But he soon caught on to the pattern.

John is always the one to initiate contact. Always the first to kiss, to touch, to shed clothing, to strip Sherlock of his. Sherlock has always ignored personal space, but he never goes further than hovering. So John always makes the first move.

And when they go to bed (or sofa, or kitchen table, or armchair, or shower, or wall; it varies), Sherlock always seems to let John do whatever he pleases to him. He never protests, never takes control. He participates just enough, John has observed, to seem like he enjoys it. But it's quite literally just enough, and after months of having sex about twice a week with this pattern in mind, John finally has to ask.

"Sherlock, do you like having sex with me? At all?" John wants to know, and he is very, very calm and seems more curious than offended, his brows lax, and that's the only reason why, John thinks, Sherlock answers him honestly.

"Yes. I wouldn't partake in the act if I didn't," Sherlock says.

And for a while, that answer is enough.

But one night, John has to make sure. He has to. So amidst their foreplay (which is, generally, a lot of snogging), John breaks a rather passionate kiss and requests lowly, "I want you to top tonight."

And yes, unfortunately, there it is: Sherlock's evident tension and hesitation. "Me?" he says.

John nods. "Yes, you. I'm sure it'll be brilliant, like everything you do."

"But I…" and Sherlock grows quiet, and that is never a good sign.

John sighs and sits up. "There, I knew it," he says, and there is no hurt in his voice, only confirmation. "Sex doesn't really appeal to you, does it? Not like it does to most everyone else. You have no…" He searches for the right words. "No hunger for it, no lust. But you still do it. Why? Just because I want it?"

"Partially," Sherlock confesses. "I can't lie, John, not when you have pieced it together. I feared you might; you are, after all, mildly intelligent."

"I'll try to take that as a compliment," John murmurs. He sighs, adjusts his hips, and touches Sherlock's cheek. "Now tell me, Sherlock: why do you let me do this to you if there isn't much in it for you?"

"My body can be stimulated like anyone else's, because anatomy is anatomy," Sherlock relays softly, "But you are correct, John: I don't possess a 'hunger' for intercourse like the general population does. But that doesn't mean I don't want to have it with you. I enjoy more the closeness than the physical pleasure; I like the bond it brings, the raw emotions that comes out in you especially bright when you make love to me, and the way you fit inside me like a puzzle I know fits together but still can't see the image it makes when it does. It is… pleasurable in thought, sex with you. I enjoy the meaning and intrigue of it, and that is why I never wanted you to think I didn't like it."

John smiles and glances down, feeling the tendons in Sherlock's hand pressed into the mattress beneath them. "I figured as much. I just wanted to make sure you weren't going through the motions or pulling away from me. But from now on, don't fake anything, okay? If you don't feel like making a noise or touching me, then don't. I'll carry on as I please, if you don't mind, but I want whatever happens to be genuine. Okay?"

"I can do that," Sherlock murmurs, and he turns his hand over to pick up John's and return it to his face. "But I must warn you, I will be doing a great deal of silent observing, then. I like to watch you more than anything else. Each movement and intake of breath and sound is fascinating."

John smiles and pressing his face into Sherlock's chest. "Is that why you close your eyes so much? To seem natural and to keep yourself from staring too intently?"

"Yes," Sherlock says, and he closes his eyes now, feels John's warmth against him where he's sitting on his own calves, settled between John's bent legs. "I could orgasm just by watching you. There is so much to ponder, to observe, when it comes to you, but never more so than during sex."

"Hmm, I'll keep that in mind. In fact, we can use that to our advantage; we haven't tried a certain position yet, and I think you'll like it, because then you can stare down at me the entire time, but I can still be inside you like you like," John suggests huskily, and it sends a pleasant shiver down Sherlock's core.

"I know precisely what you're referring to, and I can't help but thank you for being so understanding, John," Sherlock smirks, and he slinks upward and goes about preparing himself – it never takes very long – and lowering himself onto John slowly, until there is that wonderful feeling of being complete taking over Sherlock, and he sighs contentedly.

And he's able to watch John's every emotion, his hands on John's chest as he rides him, feeling every twitch of muscle and heartbeat, and he doesn't have to mask his face with cliché sex-expressions anymore as he takes in everything that is laid out in front of him, under him; everything that is purely John, and he thinks, briefly, how no one will ever get to have this because no one will get to have John the way Sherlock has him.

The magic of coincidence rears its head, too, when they finish and lie panting together, because John rolls onto his side and peers over at Sherlock and says rather possessively, "No one is as lucky as me, are they? No one will ever get to have you the way I do."

And Sherlock just smiles, and for once, he initiates the lovingly slow, post-sex kiss.