"What? Sherlock, I'm not going to do that."

"Yes you are."

"It's dangerous."

"I asked you what you wanted me to do to you. Now it's time to return the favor," he smirked.

"No, not if it's going to harm you."

"John will you just relax? If you'd rather I go in the other room and do it alone…"

"Don't do that. Just…fine I'll do it," he sighed exasperatedly. He supposed if Sherlock was going to do it anyways, it was safer with him rather than alone.

"First, put these on," Sherlock demanded, handing John black leather gloves.

John raised an eyebrow.

Sherlock rolled his eyes. "Just fucking do it."

"Fine," John said slipping the gloves on. He was still uncertain about this.

"How do I know when to stop? What if you pass out?"

"Christ, John, have you forgotten you're a doctor? I think you can figure it out," he snapped.

John climbed on top of Sherlock uncertainly.

"Kiss me first," Sherlock ordered.

John obeyed, leaning into Sherlock and kissing him roughly.

Sherlock bit John's bottom lip hard enough to make it bleed, licking the blood away slowly with the tip of his tongue.

John moaned slightly against Sherlock's lips when Sherlock bit him.

Sherlock could feel John's breathing getting heavier, his leather-clad hands twisting his hair as they kissed each other, messy and hot.

Sherlock's cock was already painfully throbbing beneath John.

Both of them were breathing hard by the time Sherlock broke the kiss, "do it."

John placed his leather-clad hands carefully on Sherlock's delicate neck, the black gloves contrasting sharply with his porcelain skin.

Sherlock felt John's grip tightening as his oxygen was slowly cut off, his hand stroking his cock. The soft leather of the gloves crunched noisily against the delicate skin of his exposed neck.

His body tried to inhale, but John's hands had gripped tightly, restricting his breathing.

Sherlock's body struggled, vainly trying to intake the oxygen that it was being deprived. His head started to swim and his train of thought slipped, his consciousness struggling desperately to grasp onto any thought.

He tried to concentrate on the feeling of the gloves against his neck, but each detail slipped from his consciousness so that the only reality anymore was the feeling of his approaching orgasm.

He tried to cough, but choked on nothing as his body trembled with spasms underneath John's weight on his chest, suppressing his lungs even more.

His hand slipped over his cock with an increasingly erratic rhythm. He shut his eyes tightly and clenched his teeth; lights flashed behind his eyelids as he felt every nerve release at once with an intense rush that was almost painful.

John released his hands and Sherlock gasped.

The sound of his ragged breathing filled the room as he tried to catch his breath.

"F-fucking. Hell," he panted.

"Don't ask me to do that again, Sherlock."

Sherlock struggled to regain his breath. "Shut. The. Fucking. Hell. Up. John," he managed in between breaths.

John pulled off the gloves and threw them angrily on the floor.

"And I want you to stop with the cocaine," he said sternly, anger ebbing into his voice.

Sherlock croaked out a laugh. "Like you have any control over what I decide to do with my life."

"I could move out."

"But you wouldn't. We both know that."

John just glared at him.

"Besides, John. You love it when I'm like this. I can see it in your face."

"Will you stop doing that?"

"Doing what?"

"Analyzing me like I'm one of your experiments."

"But you are one of my experiments, John," he stood up, still breathing heavily, and walked over to where John was standing.

"What kind of reaction would I get if I did this?" he asked himself in an amused tone and tried to lean in and kiss John.

John ducked underneath his arm.

"Sherlock, I'm serious. This has to stop."

"I can see that clearly the evidence points to the theory that the test subject is not aroused by being in control, but by being controlled," Sherlock continued in his amused, condescending tone. "The test subject enjoys it when the variable is angry. And out of control…dangerous."

Without warning, Sherlock thrust his hand out against John's neck and slammed him hard against the bookcase, knocking several books to the floor.

Sherlock leaned in, barely inches away from John's face. He spoke barely above a whisper, every word cutting sharply through the air, "You want me angry? You want me out of control? You don't know what you're asking for, John Watson. You have no fucking idea what I'm capable of."

He shoved John against the bookcase again before releasing him.

"See? Your pupils are dilated now. They weren't a moment ago. Dilated pupils are a sign of arousal," he said smugly. "Oh, and you can deal with that," he said gesturing to the bulge in John's pants, "yourself." He smirked as he walked out of the room triumphantly.