Rule number one: is that you've got to have fun.
But, baby, when you're done - you've got to be the first to run.

We're crouched inside an empty recycling bin, shoulder-to-shoulder and I know John's nervous, I can practically smell the anxiety radiating off him. He's pissed off, too - his natural reaction towards me - that we're in this wretched disposal container and we smell like a thousand unpleasant things and we're waiting to pounce on someone that we're not entirely sure is actually who we're looking for. Although, I refuse to admit to John that I'm not completely faithful in my own assumptions.

He's juddering his leg nervously and it's knocking against mine and I'm doing a frankly marvellous job of ignoring the fact that I rather enjoy the contact and instead I keep raising my head to dart my eyes above the bin. He sighs beside me and his breath seems to fill the entire tin container. He's tired and he thinks his leg hurts, as I can see him absent-mindedly rubbing it with his palm.

I force him to wait just five more minutes before giving him the good news that we can leave - I tell him that of course the suspect wouldn't come this way, as it's exactly what I thought, which is why we had to sit in that bin for three hours just to prove that my deductions were right and that he wasn't going to walk this way. Which clearly he did not, as he never passed us. So I was right. Of course I was.

With a few grumbles, John pulls himself out of the dumpster with surprising grace and surprises me further by peering over and offering me a hand up. I take it and boost myself over the edge of the bin, without failing to note that his palms were quite clammy but of course he would blame it on being in that bin for so long. However, I knew differences between many types of sweat and his damp palms were undoubtedly caused by nerves.

Let it be known that I, Sherlock Holmes, am no fool. I simply do not have time for the foolishness of most human beings. Therefore, I am not blissfully unaware of John's attraction to me, just as I am not oblivious to the fact that John very, very much dislikes these feelings of attraction towards me. He is confused and likes to chant not gay not gay not gay completely not gay under his breath to his own reflection after his morning showers. I have never broached the subject with him and refrain from doing so for his own humility. I am a decent person sometimes.

It is hard to ignore the scratching feeling in the back of my subconscious that is somewhat bothered by John's flustering around me. Attachment and sentiment make me altogether uncomfortable. It is terribly dangerous to become attached.

But there is something in the uneasy nature of John Watson that suddenly makes him very vulnerable. There is also something inside myself that would not mind at all taking advantage of John's confused feelings. If you can't have fun where sentiment is involved, then what can you really do with it?

We hail a cab back to Baker Street and John lets us in without a word. It is quite late now and I am glad that Mrs. Hudson will be asleep because I simply couldn't bear an ignorant interruption of the plans I am beginning to form for the night. I follow John's rhythmic tread up the twelve steps and into our flat. He steps out of his shoes and announces he is going to have a shower. I wait until he bolts the door before I walk into his bedroom. I don't even intend to be so quiet as I am most definitely not creeping around and I have nothing to hide and I'm really not in the slightest bit bothered that I'm stood in John's bedroom.

I try several standing and sitting positions before settling on nonchalantly sitting in the chair by John's desk, propping my feet up on the edge of the table and crossing my ankles. He takes approximately six minutes - as I had estimated - in the shower and pads into his bedroom in his towel. He seizes up as he sees me sitting here before that familiar adorable look of annoyance takes over his features.

"Sherlock, what the hell are you doing in here? Get out!" I laugh at the futility of his words and turn to observe him. Even I cannot deny how aesthetically pleasing it is to watch the beads of water drop from the hair at the nape of his neck down his shoulders. I make a conscious effort to keep my eyes above board.

"I have a question for you, John," I state matter-of-factly. He opens and closes his mouth a few times, trying to find some choice words, before settling and saying nothing at all. Good, John. "Remember the first time we met, that evening in the restaurant? You asked me if I had a boyfriend."

"Or girlfriend," he adds hurriedly and defensively.

"I was distracted by the case at the time, but I have now decided I would like to pose a similar question to you: have you ever been with a man?"

He chokes on his tongue and tries to keep his composure. We are both blissfully - on my part, anyway - aware that he is very much naked underneath that tiny white towel and John wishes nothing more than for me to get the insert various curse words here out of his bedroom so he can dress himself. I am more than attuned to what his body language is screaming at me but I choose to ignore it.

"No, Sherlock… No, I haven't. Why would I have- I mean, I'm not gay, Sherlock. I'm not gay-" he's babbling for some kind of self-assurance about his sexuality and he just keeps getting more appealing. To tell the truth, I am horridly inexperienced in all things sexual and somewhere in my gut I am feeling far less cool than I am letting on. However, I find teasing John far easier than mulling over my feelings for him. Whatever those feelings are.

"Okay," I say pensively. "But I'm sure you've thought about it. I mean, it doesn't make you gay, John. But have you thought about it?"

"Sherlock, I-"

"I have," I continue, not allowing him to finish his sentence. It is becoming increasingly easy to lower his not gay defences. I put myself into the same frame of mind that I adopt for conducting experiments or working on a case - detached, because after all this was definitely just another kind of experiment but it was one that happened to allow me to breach the usual social restraints with my inconveniently attractive flatmate whom I may or may not have had several accidental wet dreams about. But obviously all that is classified information and is very securely locked away in the farthest region of my mind palace, guarded by angry pit bulls. "Would you to know what I've thought about?"

I jump from the chair enthusiastically and come to stand before John, who shifts self-consciously. His wet hair is dripping in his eyes and I'm waiting for him to tell me to piss off, no he doesn't want to know what I've thought about doing with another bloody man, yet no sound comes from his mouth and his cheeks turn just that shade of darker pink.

"You've kissed women before, John, as have I. But imagine how different it would feel to kiss a man," as if to emphasise my point I allow my eyes to drift to John's own lips, which look the perfect moisture as he has just licked them as a nervous response to me talking about kissing him. I mean, kissing another man. Not him specifically. That would be ludicrous. "Strong hands gripping your shoulders and crushing their mouth to yours. Pushing you back against the wall and boxing you in. Not worrying about breaking you - nothing like a woman; some of them are so fragile you can barely handle them without hurting them."

His eyes are darting from my eyes to my lips back and forth back and forth and I really hope he doesn't think that I haven't noticed or else he certainly doesn't know me as well as I assumed he does by now. He wants to kiss me, I'm so sure of it and I kind of want to kiss him too but purely for experimental purposes and because making him flustered and needy is my idea of fun when there are no suspicious murders to be solved.

I take slow, deliberate steps forward and, as anticipated, he takes fast, frantic steps backwards until his back is against the wall and I am towering over him and he's utterly helpless. He isn't afraid but he is confused and almost certainly ashamed that he isn't stopping me. I place my hands on the wall either side of him and tilt my head down to his face. I hover my lips an inch above his, testing the waters even though I know he's going to let me kiss him. His anxious breaths tickle my face and I close the gap, carefully pressing my mouth against his. It takes a minute for him to react and at first I think he's going to surprise me by pushing me off him, as he plants his hands against my chest but instead he grabs the back of my neck and crushes our lips together even more.

Embarrassingly, a low hum of appreciation erupts from my throat and I'm kissing him again with more force this time and he parts his lips so I slip my tongue in and it's like I've kissed a thousand men and all of them were John Watson. I am so content exploring this man's mouth that I almost forget that this kind of stomach-flipping activity is completely and utterly out-of-bounds for me, not to mention highly dangerous and not even the good kind of danger because you can never ever associate sentiment with the good kind of danger.

I snap back to reality as I realise that I no longer have the upper hand here, since John has become too confident in kissing me. I pull back and drum my fingers down his bare, rapidly drying chest and John is back to feeling uneasy and nervous. His breath is quicker, as is mine but his hitches completely when my hands find the top of his towel which is loosely knotted to keep it from falling to his feet and exposing the entire Dr. Watson package.

He looks at me with doubt at first; he doesn't think I will really drop his towel. Even though I am anxious to my core as I have never had any sexual experience with a man, I just simply loathe being wrong so I bite the bullet and fiddle with his towel, holding it up myself and looking him square in the eye before letting it flutter to the floor and I feel such glee because of John's reaction.

I don't even have to look down to know that he's getting aroused already and I know he is painstakingly aware of this fact too. I lean in to his ear and I'm kissing and licking and sucking, his ear his neck his shoulder his chest and he's breathing so hard it's hard for me to keep control and remember that this is just me having fun and embarrassing John Watson and it's nothing to do with the fact that God I'm turned on right now and wow I definitely didn't expect that to be hiding in John's pants and Jesus Christ what do I do now.

The only thing I can manage to do is cage his face in my hands and kiss him again with so much need that it's almost embarrassing and I'm praying that he can't tell I'm a little desperate. We're clumsy this time, banging teeth and stumbling backwards and suddenly I'm lay on John's bed and he's hovering above me and I find myself yet again not in control so I flip us over and I'm leaning above him now.

My lips are bruised but I don't stop and I'm biting his shoulder and he's gripping my arms and I'm shuffling out of my trousers and peeling off my shirt and suddenly I'm a lot more naked than I was before. John is grinding against me, desperate for some friction and I can't help feeling the same way. I reach my hand between us, using the other to prop myself up, and help him out. He groans so loudly that I think Mrs. Hudson will wake up and find us in this compromising position.

We're at this for a while and I know that I need to keep my head in the game but I keep getting lost in all that is John Watson. I decide the only way to regain control of this situation is to seize it - with my mouth. I pin him down and trail my mouth down his body; he shudders as I reach that spot I know he's been craving my mouth on.

He's fisting his hands in my hair and I'm gripping his hips so hard I know he will have fingertip bruises all over them tomorrow but I couldn't care any less than I already do because I want him to remember all of these events until those bruises yellow and fade away.

He's close now and I've nearly completed my mission and when he comes it's almost enough to untie me completely and he's barely touched me. I want him to, I really want him to touch me but that's not part of the experiment and it will definitely absolutely invalidate the findings.

John lies panting and my arousal is uncomfortable. I want to kiss him again but that would be inappropriate as I have done all that I intended to do. Anything else would be unnecessary surplus and quite possibly a result of some kind of inconvenient emotional attachment. And I'll be damned if I start feeling sentimental over John Hamish Watson.

I hop up off the bed with a final wink in John's direction and slink back to my room to finish myself off. I can imagine John's confused face, post-coital and perhaps… Hurt? Hurt that I didn't stay? I batter the pang of guilt out of my stomach with an iron baseball bat and remind myself that John isn't even gay, remember? He says he's not. But I know that no straight man would participate in such activities and not question their own sexuality.

I lie back in bed after cleaning myself up and smirk. Oh, how good it feels to have shaken up the army doctor so very much. I just wish these irritating feelings of fondness would get the hell out of my way as they are making it increasingly difficult not to blur the lines between experimental and sentimental.

I just adore a good song-fic. The song, by the way, is How to be a Heartbreaker by Marina and the Diamonds.

I was listening to this the other day and was laughing internally on the bus imagining Sherlock as the bitchy, I-hate-emotions-ew-so-gross-gotta-be-a-heartless-user persona in the song but, of course, he can't ignore those damn feelings for John Watson. (Nor can I.)

I will post a chapter for each of the 4 "rules" that make up the lyrics of the song. Let me know how I did!