A/N: Ok, so for anyone who has read my other stories. This is NOT like those! I was feeling grumpy and edgy and wrote what pretty much amounts to porn. Plot is kept to a minimum to maximize smutty sex scene. :P This was written for a picture prompt that I can't put here cause a) it's a picture and b) it's hotter than the sun but totally inappropriate for this site.

I'd like to thank my wonderful beta Rheadyn and applaud the fact that our friendship lasted through that awkward moment when your friend confesses that she just wrote a kinky sex fic. :)

Disclaimer: Sherlock is not mine, I'm just playing with the characters.

Warnings: Slash and bondage… if that's not your cup of tea, I suggest you run away like the hounds of Baskerville are after you.

The Experiment

"John, I need you for an experiment."

"What kind of experiment?" John asked warily. He had learned his lesson about Sherlock and experiments… the hard way.

"This one won't turn your hair green, I promise." Well, that was reassuring at least.

Sherlock didn't wait for his consent, —when did Sherlock ever wait for consent?— just grabbed John by the shoulders and spun him so that he was facing the wall. John's arms were pulled behind his back and he experienced a moment of pure shock as he realized what was going to happen a moment before it did. Something rough and firm, a belt perhaps, was looped around his wrists and pulled tight.

"Uh, Sherlock? What are you doing?"

"Isn't it obvious? I'm recreating the crime scene."

John swallowed as he remembered exactly what the crime scene had been like.

"I'd like to unvolunteer for this experiment." John said thickly.

He was spun around again to face Sherlock whose eyes were brimming with barely suppressed excitement.

"Come now, John, there are lives at stake."

"You're only saying that to make me comply."

"Yes." Sherlock grinned evilly. "Now get on your knees."

John's knees hit the floor. Not because Sherlock had told him to —Okay, maybe a little because of that— but because most of the blood in his legs was quickly relocating to… other areas.

Being tied up by your insane flatmate is not sexy, John told himself strictly. I beg to differ, said the more honest part of his brain. I'm not even gay, he reminded that part. No, you just find Sherlock's deep voice, big hands and icy eyes extremely arousing. John felt like banging his head against a mental wall; trust Sherlock to force him into a sexual identity crisis against his will.

"Right, so he was on his knees, we know this from the scratches on the skin. And he was naked, of course." Sherlock looked at John contemplatively.

"Sherlock, no!" John said, a little panicky. "I am not getting naked!"

"You're not being very cooperative, John." Sherlock pouted.

"You're not being very reasonable!"

"Fine, just your shirt then." And without giving him any time to protest Sherlock quickly unbuttoned John's shirt and slipped it down his arms.

John's mouth was very dry and his rather unprofessional interest in the proceedings was beginning to show.

Sherlock didn't seem to notice.

"Next, they interrogated him. But he wouldn't give them the information. No, he was tougher than that, stubborn too. So they beat him. Here" Sherlock swiped one polished Italian shoe across John's stomach, the cool leather making his muscles quiver. "Here." He touched the overly sensitive tissue around John's scar. "And here." His fingers brushed across John's cheek, then his lips. The touch was almost clinical in nature but it sent John's heart into overdrive.

"Of course, that didn't yield any results." Sherlock continued, pacing.

Oh, it was yielding results alright. John was now fully aroused and his groin was throbbing in time with his heartbeat. And all he could think about was that he was on his knees. Tied up. Vulnerable. With Sherlock towering above him, in control and dictating logic in that sexy voice he reserved for murder cases.

"So what would they do next? They couldn't kill him, not right away, they needed the information."

Sherlock stepped in front of him and suddenly John's eyes were level with Sherlock's crotch. And that sent his mind down paths it had no right treading. But then Sherlock slid one long-fingered hand into John's hair and his breath caught in his throat because, no, Sherlock couldn't—

His head was tugged back till he was looking up into Sherlock's frustrated gaze.

"Are you paying attention, John? This is important." He said.

"Uh—" John gave himself a hundred points for not moaning.

"Think, John. Think! What are we missing?"

"More rope." Also his brain. Did he just say that out loud?

Sherlock blinked which was code for I've-just-had-a-revelation.

"Of course. The marks on his neck, they weren't from bacteria infection. Anderson's an idiot! Well, we knew that already." Sherlock disappeared from his field of view. "Rope. Yes, there was something around his neck."

John felt cool material slide around his throat. Oh God. This is a strangulation hazard, not hot bondage foreplay, he told his raging libido. It ignored him in favour of playing with the thermostat of his body. The strap around his throat tighten. Not to the point that he was choking but just enough that he could feel his every breath and swallow. John's thoughts went hazy with desire.

Sherlock was muttering in excited tones behind him but John couldn't keep up with the words anymore. His knees were becoming sore and his left shoulder was protesting the awkward position but each throb of pain just sent more blood to his already straining erection.

Suddenly there was a tug on the restraint around his neck and he found his back flush against Sherlock's chest. The detective's mouth hovered just beside his ear and John could feel Sherlock's breath on his neck.

"You've been very good, John." Sherlock whispered. "You deserve a reward."

John groaned. Because no, Sherlock did not mean it like that. He was asexual and in a monogamous relationship with crime and—

Warm fingers brushed his side and skimmed lightly over his stomach.

"Anything." Came the husky whisper in his ear.

John's breath escaped on a moan.

"Do you have any idea how you look right now? Flushed, chest heaving with your breathes, your eyes half-lidded. You want this." Sherlock pulled John's head back till he was looking into piercing blue eyes. "Tell me know want this, John."

"I want this." John sobbed.

Sparks ignited in Sherlock's eyes. The hand on John's stomach swiped tantalizingly close to the place where he wanted it most.

"Tell me that I can do anything I want with you."

YES! God, yes! "Anything" John breathed.

Sherlock's smile was positively sinful and John had one terrifying moment to think about what he had just agreed to before warm lips crashed down on his and he stopped thinking altogether.

Sherlock kissed much like he did everything else in life: unabashed, unapologetic, taking whatever the hell he wanted. Scorching. A clever tongue touched his lower lip demanding entrance, followed quickly by sharp teeth when he didn't part his lips fast enough. And then Sherlock's tongue was in his mouth, tracing the contours, learning it like a map. And John could taste him. Him and nothing else. And he tasted like danger.

A/N: Part 2 will be up soon, just need to hammer out a few things.