Longing. A word easily broken down into two syllables, seven letters and a dictionary definition. By all means, a relatively short word taught to most children around halfway through their elementary schooling. An emotion Sherlock would've instantly regarded as, "Dull." But still, an emotion. A feeling associated with love, passion, lust and heartbreak.

All things he's never experienced. All things he likely never will.

When you can't feel love, there's no way to understand it. You can't break it down with a physical explanation or demonstration. It's just… there. And Sherlock, being a man of science doesn't believe in something he can't see, touch, or smell. The closest I came to putting it into understandable terms for him was saying 'It's a bit like dust, or bacteria. You can't see it, but you know it's there.'

Sherlock frowned. 'I've been widely informed it is much more pleasurable than germs.'

Leaning my head against the cab window, I attempt to soak the cold glass into my skin. Even in the darkness, alone, I won't close my eyes. The first thing I'll see is his face, and suddenly the hole in my chest will grow a bit deeper and wider. So I pry them open a bit wider, and even after a long day at the clinic, the last thing I want to do is go home. Where he is. Where he takes my stuff without so much as a glance towards me to ask for my permission and where he will touch me fleetingly on the shoulder in a way that reminds me of his presence. It does much more than that, realistically. It sends my nerves on a never-ending trip to heaven and back, feeling both fantastic and agonizing at the same time. Because those little touches I'm given, those small tastes and glimpses are what a life with Sherlock would be like. A life where Sherlock loved me, too.

Butterfly touches, I call them, as they are so light and delicate. The best way to describe them would be to compare them to having only one piece of chocolate—so hard not to have another, yet another leads to another, and before you know it, you've eaten the whole thing. With Sherlock, if I allow myself to lean in just the slightest, the urge might be too much to hold back.

It's three in the morning by the time I get home, and for once, he's actually asleep, lying in an awkward fashion on the couch. I take every precaution not to wake him, tiptoeing around the flat in a ballet-like fashion, avoiding flicking on lights. His breathing is smooth and deep, and when he lies still like that, outlined by only the light of the streetlamps, flickering inwards from the window, he resembles a Greek God. He's stripped off his jacket on the floor, and his skin is like raw, white silk thrown over his bones, making him look halfway between sinful and angelic, but flawless none the less.

No, Sherlock would never have any concept of longing. But I did. And tonight, above all other nights, I will give into it.

He can never know. This must look like it never happened. Just one taste. A sample, if you will, to indulge myself with on just this occasion.

I start slowly, running two fingers along his cheekbones lightly, succumbing to the warmth of his body and letting my lips land in his curls—the colour of Italian coffee, I decide. My heart pounds faster in the darkness, and I have to remind myself that he's asleep, and can't reject me. Finally, I lean over him upside down, pressing his soft, warm lips to mine in a kiss so delicate it would break if dropped on the ground. His lips are supple and I yearn to nibble on them gently, but he would deduce come morning as to why they were swollen, and would confront me with it.

I cup his chin gently, allowing my own lips to surround his lower one, bathing in his alien scent that was both erotic and sensual. I moved my mouth and his in synchronization, my heart beating so fast it must be a blur in my chest and my breathing growing ragged in my chest. My gaze flicked to his chest, barely concealed by a see-through white shirt and I found my hands leaving his face behind and burying themselves under the cotton and…

…stop. I need to stop.

Longing. A two syllable word with seven letters and a dictionary definition. An emotion Sherlock would never feel. An emotion I really wish he'd feel.

Probably the most painful one in the world.