Moriarty put the knife against Sherlock's neck, the cold steel glinting. He pulled the blade slowly across his skin, Sherlock wincing with pain as he gritted his teeth. A red line trailed after the blade, spilling over the little parted walls of flesh. The cut was deep enough to make drops race down his porcelain white neck, but not deep enough to seriously harm him.

Moriarty's eyes followed the trails of the drops of blood down his neck. He lowered his head and traced the red line with his tongue. Sherlock shivered and his hands strained against the handcuffs, which were too tight and digging into his skin painfully.

He would have protested as Moriarty lowered the blade to his skin again, but a bit of cloth had been tied around his mouth, gagging him so that he could only moan.

"Shhhh. I know you like this Sherlock, there's no need to pretend," Moriarty mumbled into Sherlock's hair. He opened his mouth to say something more, but only a groan of pleasure escaped as he continued to thrust into Sherlock.

"You are so goddamn…" he trailed off as he gritted his teeth. He pulled out, not wanting to end this too soon.

"Sherlock. Don't struggle and it won't hurt so much," he said shaking the handcuffs, making Sherlock wince.

He raked his hands along the length of Sherlock's body, fingernails trailing from his chest, down his abdomen, across his thighs.

Moriarty watched Sherlock's skin react with fascination, trembling at his fingertips. His fingers danced lightly on Sherlock's hipbones, jutting from his thin frame, before his hands settled on his hips. He lowered his mouth down as he made eye contact with Sherlock. He watched as his expression changed drastically, from pain to uninhibited pleasure, unable to hide.

Moriarty ran his tongue sloppily around Sherlock's cock. His hips started bucking with Moriarty's rhythm, Sherlock no longer trying to stop himself, coming close to orgasm.

Suddenly Moriarty sat up, wiping his mouth obscenely with his hand, flinging saliva.

"What if I left you like this, right now? You are so fucking desperate," he said as he noted Sherlock's hands straining painfully against the cuffs, desperately wanting, needing to push his head back down.

"But what would the fun be in that?" His voice was too light, too playful for the situation. He was almost sadistic, beside himself and worryingly amused with the inappropriateness of it all.

"You know you can't blame me. We both know you're not an idiot. And yet you're the one who came on to me. You're so obsessively curious that you just can't help yourself. You wanted to know what makes me tick, you wanted to get close enough to observe me, experiment with me, with my…limits."

He put his face next to Sherlock's, his breath on his face. "Is this close enough, Sherlock?" he whispered. "Do I live up to your romantic views of the psychopath? Am I every detective's dream to decode?" he smirked.

He swiped two fingers against the blood on Sherlock's neck. He moved his fingers around, watching the bright red glisten in the light, almost fascinated.

"I want to see how much you can bleed," he said too nonchalantly to be sane.

Sherlock struggled against his restraints and Moriarty fingered the point of his knife. He suddenly dragged it down his own wrist, mesmerized at how fast the blood started to flow. He let it drip onto Sherlock's chest, hot and vibrant.

"I want you to taste my blood. I want my blood on your tongue," he said, shuddering slightly with anticipation at the sudden reality of his twisted fantasies.

"Now, will you be a good boy and remain silent if I remove your gag?"

Sherlock nodded.

Moriarty smirked. "Somehow I doubt that," he mumbled, more to himself.

He leaned forward and untied the cloth around Sherlock's mouth, removing it slowly to gauge his reaction.

"You aren't going to yell? Aren't going to call me names?"

"No point. Obviously you aren't an idiot either. No one is within hearing distance of us, and anyway it would probably just excite you more," Sherlock said with more calmness than he felt.

"You are good. That's why we're so perfect for each other. We're so alike. Because admit it or not, Sherlock, you're not bored right now. We're a match. No one else could ever come close to rivaling you. Or me. The sooner you realize this, the less bored you'll be. Because admit it, that simple army doctor," he almost spat the words, "could never –," his sentence was suddenly cut off as he doubled over in pain after Sherlock had kneed him in the groin.

"Don't. Bring him into this," Sherlock said sharply through clenched teeth.

"You really, really shouldn't have done that," Moriarty said darkly, his eyes clouding over. "Need I remind you who the one in handcuffs is? Don't disappoint me by acting like a common idiot, because I have no qualms about killing common idiots. The only reason you're still alive is because you're worthy of it, you're different, you're not a common idiot, Sherlock."

Sherlock just glared, hating him. Hating him for being right about the two of them.

"Fuck off."

"As much as I love to hear you talk, darling, I must insist that you remain silent before you push me to do something I will inevitably regret," he said roughly fixing the gag around Sherlock's mouth again.

"Now, where were we, sweetie?" he said in mock affection. "Ah yes. Blood."

He pressed the point of his knife against Sherlock's cheek, though not hard enough to puncture the skin.

"You're so goddamn beautiful. I would hate to mar that perfect skin of yours," he made a noise that was almost like a giggle. "Where should I cut next?"

He traced the point of the knife lightly across Sherlock's skin as he flinched.

"I know," he said, the knife coming to a rest at Sherlock's right shoulder. "Since you like idiot army doctor so much. Your pet."

Sherlock's eyes flashed with anger, rage. It quickly turned to intense pain though as Moriarty dug the edge of the knife into his shoulder without warning.

"I'm so sorry, darling," he whispered not with regret, but with a sense of excitement.

Moriarty cut deep. Blood was pooling quickly beneath Sherlock and staining the sheets deep red. He lowered his lips to the wound, his tongue teasing it painfully. Then he closed his mouth around it and began to suck. He moaned with an animalistic urgency.

The obscenity of the whole scene was absurd. For once in his life, Sherlock had made a mistake. He read Moriarty wrong. Not wrong, exactly, but he had definitely underestimated him and how much of a complete psychopath he was. He was drinking his blood for Christ's sake.

A film of clammy sweat was now covering Sherlock, who was shaking from the pain. He tried to keep silent, but he couldn't stop the groans of pain that accompanied every flick of Moriarty's tongue.

Moriarty lifted his head, blood dripping grotesquely and barbarically from his mouth. Both them looked pale against the deep red of the blood, though Sherlock more so.

Moriarty pressed his right hand against Sherlock's shoulder, causing him to cry out in pain, the sound muffled against the cloth.

His hand coated in the hot, sticky blood, Moriarty started to move his hand up and down his cock, his hand slipping easily over it with Sherlock's blood. Braced over Sherlock, he lowered his head once more to lick and suck the wound, which was bleeding with an alarming urgency.

Sherlock was feeling lightheaded now and he felt a sense of panic breaking down his usual composure.

Moriarty was breathing heavily, each breath labored with ecstasy. He moaned loudly and desperately, mumbling Sherlock's name as he came hard, semen mixing with blood.

As he came down from his orgasm, he kissed Sherlock's forehead, leaving a bloodstained print.

"Think about what I said next time you're bored. I know you will. Your mind won't leave it alone, because you know it's true and you could never consciously deny yourself the truth. We were meant for each other, Sherlock. My consulting detective. You are mine. And I, yours," he gently brushed a lock of hair out of Sherlock's face, though he flinched at his touch.

"Don't be like that. I'll be nice and call you an ambulance. You might need surgery, definitely stitches. I really am sorry."

He unlocked cuffs, but Sherlock was too weak to move from the loss of blood and the intense pain.

"I'll see you later, darling. Be expecting my call," and with that, he walked out of the room as if it were the most normal thing in the world.