John was in the kitchen getting ready to make a cup of tea when he heard the distinct series of sounds. A series of sounds he hadn't really heard intimately since Afghanistan. Sounds he didn't realize he'd missed. The sharp metallic click of a lighter, a long slow inhale, the sizzle of paper and dried plant matter catching. With a sharp intake of his own, he marched into the living room.

"Sherlock! What do you think you're doing?"

Sherlock stretched out extravagantly on the couch before he pursed his lips and inhaled, pulling in another long slow drag before raising an eyebrow eloquently at the smaller man. "Really, John." he drawled, letting the smoke pour out of his mouth. "I know your deductive powers aren't quite as sharp as mine, but surely even you can figure this one out."

"Yes, yes, very amusing. But you know you shouldn't be doing this!" John huffed, shifting his weight from side to side as if slightly uncomfortable.

"Shouldn't I now? Enlighten me as to why not."

John paused for a moment, mesmerized by the way that soft, supple mouth wrapped tightly around the filter. He gulped, trying to compose himself and hoping his infuriatingly observant flatmate wouldn't notice that his physical bearing was shifting further and further from annoyed to aroused.

"Well, you yourself have stated how difficult a smoking habit is to maintain in this city. I'm sure you're well aware of the health-related risks, but considering some of the other nonsense you subject yourself to, I'm not sure that's much of a deterrent. It's unsanitary - you're already trailing ash all over Mrs. Hudson's rug, and you know she won't be pleased about that. And, lastly..." John trailed off and swallowed uncomfortably, well aware Sherlock was following his bobbing adam's apple with his eyes. "It's... distracting."

Sherlock considered for a moment before pulling in another lungful. John rubbed the bridge of his nose, preparing for the onslaught of inventive invective he was about to endure. Instead, the detective opened his mouth and, with a series of muffled clicks emanating from the back of his throat, expelled a series of perfectly formed, perfectly spaced smoke rings.

"Dis- trac- ting." He drew the word out, exhaling while talking and inhaling pointedly between each syllable while fixing his mirror-like eyes on John. "Could it be that the gooddoctor has a bit of a smoking kink?" His voice, delicious to begin with and slightly roughened by the smoke in his throat, dropped to an obscene rumble, and John felt whatever self-righteous indignation he had left slinking away like an embarrassed cat.

John flustered and felt the tips of his ears heat up as a blush creeped across his face. "I-" he stammered. "Well..."

"Surely someone with your vast medical knowledge should know better than to encourage a habit like this. There's got to be a reason for your interest. Someone in your past, perhaps?" Sherlock drawled, but his voice was quickly losing its sarcastic edge. "Or is it more of a sensory thing?"

"It's a good way to draw attention to the mouth, the hands." John tried to compose himself somewhat. "And with that mouth, those hands..." he gestured vaguely in Sherlock's direction, losing whatever control he'd had on the situation when his eyes were drawn to Sherlock's long, elegant fingers wrapping themselves around what remained of the cigarette.

Elegantly extracting himself from his sprawl on the couch, Sherlock stood up and stubbed the butt out on the wood of the end table, causing a strangled gasp that managed to combine irritation and arousal to escape John's lips.

"Well, well, Doctor Watson. The things I learn about you never cease to surprise me." Sherlock took a few steps forward, closing the gap between the two men, and insinuated himself into John's personal space. The smell of tobacco on the taller man's clothes and breath made John shudder slightly, his own breath increasing in pace. "Why don't I take you to bed so I can wrap my lips and hands around something else, see if I can distract you that way?"