Disclaimer: I don't own Sherlock.

The Solar System

Sherlock stared at the thread of chocolate clinging between John's finger and the bowl. John saw him lick his lips. They were extremely dry, contrasting richly with the sweat dewed across his forehead and cheeks. Across much of his figure in fact.

He made a low sound between a groan and a whine and writhed against the bed, yanking fruitlessly on his bound wrists. John had used the tie from Sherlock's dressing gown and it proved to very effective in weathering even the most violent attempts by Sherlock to free himself in the brief moments of blind desperation that overtook him sporadically.

John stood before him. His shirt was damp and clinging to every inch of his torso and arms. Sherlock's bedroom felt like a greenhouse. He could feel his hair clutching at his clammy forehead.

Sherlock rocked his hips in a helpless fashion. "John... enough," his voice was low. It sent a shiver of electricity down John's spine. "Just- just take me."

John shrugged and sucked the chocolate off his finger with a soft sound of suction. "But you haven't earned it yet."

Sherlock groaned in frustration, closing his eyes. There were smears of chocolate on his neck, on his lips, on his chest, on his thighs. John's sticky fingerprints were dotted down the inside of his hips and the curve of his slight waist. It looked brilliantly rich against the ethereal whiteness of his skin.

It took every ounce of John's frayed self-control to keep from giving in to Sherlock's demands. He wanted to. The throbbing, heated pulse that had been persistently throbbing between his legs for the past thirty minutes wanted to. But he was making a point.

He knelt on the sweaty mess of covers and dipped his finger pointedly back into the bowl, letting the chocolate pour smoothly down from his skin like a miniature waterfall. Sherlock's eyes were fixed on it and every so often a feverish heat burst through the blank void of his eyes.

John cocked his head and trailed his clean fingers down Sherlock's ribs, knowing the feather light touch was driving him insane, knowing that he was almost suffocating from the attempt not the moan. "Mercury..." John said, eyes fixed on Sherlock's damp, bleary expression.

Sherlock glared at him and bit his lip as John's fingers touched the trembling skin beneath his navel. "Mercury..." he croaked, opening his mouth with a pant."Venus..."

John smiled and leant forward. "Very good." He pressed his mouth to Sherlock's neck. Sherlock's skin was a messy mixture of salt and chocolate.

Sherlock shivered against him. John linked the remainder of the chocolate away in meaningful strokes with his tongue. Sherlock's breathing seemed to become more erratic with every movement.

"Mercury... Venus..." Sherlock gasped, as John bit down gently on his skin. "Ah! Stop- Mercury, V-Venus... Mars-"

"No," John said, breaking away and shuffling back on the bed. "Wrong."

Sherlock blinked at him. "Jupiter?"

John raised his eyebrows. "You're not even trying. I can leave you like this all night. It really doesn't bother me."

Sherlock's jaw slackened. "No! I mean... I know them. I know them. Just... give me another chance."

John licked the chocolate off his fingers. Sherlock watched him, his eyes fixed on John's mouth. "Ok. Begin again."

Sherlock took a shuddery breath in. "Mercury, Venus..." He watched John intently, as though trying to sear the answer out of his skin. "Mercury, Venus... Earth."

John smirked. "That should have been an easy one."

He dipped two fingers into the melted chocolate and smeared it from Sherlock's nipples to his navel. John left a snail trail of saliva and chocolate on Sherlock's skin. Sherlock writhed against him, arching himself into John's mouth.

He straightened up, wiping the mess from his mouth with the back of his hand. Sherlock stared unfocusedly at him. Half of his hair was disturbed from where John's sticky fingers had been through it. "Can't... anymore..."

"Yes, you can," John said, resting on his heels.

Sherlock shook his head at him. He was brilliantly flushed. His erection was beginning to leak. It had been sorely in need of attention for the last twenty minutes. John's practiced movements against Sherlock's erogenous zones hadn't helped. Not that Sherlock was fully aware that John had more or less mentally mapped out every spot on his lovely figure most likely to drive him to distraction.

"We'll do two more today," he said at length, giving in to Sherlock's expression. "What comes after Earth?"

Sherlock made a frustrated sound, and yanked on his bonds. "I don't know," he said irritably. "Who cares!"

"I do," John said. He scooped up more chocolate between two fingers and looked at Sherlock, trembling gently on the covers.

"What... what are you doing?" Sherlock said uncertainly, as John lowered his fingers to Sherlock's straining sex.

John didn't reply. He smeared it over the flushed glans. Sherlock inhaled abruptly with a sound precariously close to a squeak. "John!" he choked.

"What comes after Earth?" John said softly, touching the underside of Sherlock's shift gently with his fingertips.

Sherlock gaped at him. He licked his lips furiously, his hips jerking involuntarily against John's hand, desperately trying to create more tension but never succeeding. "Jupiter..."

"No," John said, reducing his touch to barely more than the slightest grazing of his fingertips against Sherlock's painfully aroused flesh. "Try again."

Sherlock took in a desperate gulp of air. "Ne-Neptune?"

John shook his head with a sigh and removed his hand. "Wrong."

Sherlock moaned. "Oh, God. Mercury... Venus, Earth and... and..." He sunk his teeth into his bottom lip. "And..."

John raised his eyebrows expectantly.

"Ma..rs?" Sherlock said softly.

John smiled. "Excellent."

He lowered his mouth to Sherlock's erection. Sherlock jerked his hips in anticipation, the anxious shivering returning. John teased the chocolate sodden glans and Sherlock gave a convulsive jerk.

"John..." he panted. "John... please. Please don't tease me."

John smirked against the heated tip of Sherlock's erection. "A little knowledge is a powerful thing isn't it, Sherlock?"

"Shut up," Sherlock said in a muffled voice. It sounded like he was biting his bottom lip in a desperate bid not to cry out.

John sucked the remainder of the chocolate up and leant up to kiss Sherlock with his chocolate smeared lips. Sherlock struggled into the kiss, his hands still bound firmly behind his back. John took pity on him and struggled around him to untie them.

Sherlock protested the loss of his mouth and tilted his head towards him while John struggled with the knots he had tied around Sherlock's wrists. He had thick, tie-width welts on his wrists when he finally managed to tug it away.

John traced them with a finger. Sherlock snatched them away, turning around abruptly to face him. He shoved John against the bars of the bed and began attacking his mouth in earnest. John gulped for air between having his mouth plundered by Sherlock's none-too-gentle kiss. He still had his jeans on and Sherlock's hands were soon working furiously on the buttons and zip, refusing to surrenders his lips for a moment.

John felt his jeans slip down his thighs. He took Sherlock firmly by the hips and dragged him around to face the wall. Sherlock fell against the bars of the bed, grasping it panting. John pushed himself against him and they gave a synchronized moan.

"Lube?" Sherlock said hoarsely, struggling to look at him over his shoulder.

John nodded and hastily slid off the bed to fetch it from its usual place in Sherlock's sock drawer. When he returned, Sherlock was desperately touching himself. John gave his thigh a sharp slap. "Stop that. You're not putting all my hard work to waste."

"Stop dawdling and hurry up," Sherlock said through gritted teeth.

John covered two of his fingers with gel, rolling his eyes at his friend's usual impatient petulance when it came to sex. He had no sense of romance. He lowered his fingers to Sherlock's entrance. Then, he paused. "Largest planet in the solar system?"

Sherlock jerked his head towards him, his eyes narrowed into slits. "I swear I will throttle you-"

John shrugged and rested his fingers against the sensitive hole. Sherlock trembled against him. "John... please..." he said, tossing his head with a whimper.

"Largest planet in the solar system," John said stubbornly, slipping it in a bare half inch.

Sherlock arched his back with a helpless cry. "Jupiter! It's fucking Jupiter! Now fuck me, you fucking prick!"

Not much could induce Sherlock Holmes to use profanity, but being denied satisfaction was one of the few things that did. John rolled his eyes to himself, but did as he was told. He slid his fingers inside of him and was rewarded by Sherlock's fretful string of formless words and moans.

When he extracted his fingers, his own erection was beginning to throb and ache unbearably. He gripped Sherlock's waist.

Sherlock was hanging off the bars of the bed, his back hunched and drenched with sweat. Every time he exhaled his whole form shivered. "Now, John," he mumbled thickly.

John eased inside of him. The tightness and warmth momentarily blinded him; he let out a breathless gasp. He always forgot to move until Sherlock's irritated: "John. Move." snapped him into action.

He nodded stupidly, forgetting that Sherlock couldn't see him and began to fuck his friend in earnest. It was a good thing Mrs Hudson was out shopping, the bed made a terrific amount of noise against the wall and the springs tended to groan as well.

"Harder!" Sherlock ejaculated between John's rough thrusts.

John let out a taut groan, trying to do as Sherlock said without completely losing control. For all his enthusiasm, Sherlock was always very vociferous in his complaints the morning after when he couldn't walk without a telltale limp. Their collective horror was that Lestrade or Anderson would notice Sherlock's limp and the welts on John's arms and put two and two together. Sherlock seemed confident that they wouldn't. After all, they were "imbeciles who wouldn't notice a Mardi Gras float if it ran over them in the street."

Sherlock's breathing built to a frantic level. Somewhere in John's foggy, lust drunken mind he could hear Sherlock inhaling and exhaling in shorter and sharper spurts. The bed was beginning to hit the wall at an almost dangerously fast pace. John could imagine the dents in the wall that they were going to leave after a few months of this treatment. He could only hope they never moved or Mrs Hudson would probably make them pay hundreds in repairs.

"Oh, John," Sherlock moaned, tossing his head. John got the impromptu desire to sink his hand into Sherlock's thick, dark hair and clutch it tight. "Uh... God. Oh, fuck-"

John took a desperate breath of air; his fingers were beginning to slip on Sherlock's hip. He closed his eyes, as Sherlock's words began to morph into a string of heated, bearable audible profanity.

"Fuck," John growled. "Fuck!"

His orgasm burst violently over him like a wave. The fingers threaded through Sherlock's rapidly tightened and the hand curled around Sherlock's hip sunk deep into Sherlock's flesh. Below him Sherlock gave a violent shudder and John knew he was climaxing too.

"John!" he cried out into the perfect silence of their room.

John rode out his orgasm is slow waves. He forgot to breathe until his lungs felt like they might burst. He desperately gasped for oxygen. Sherlock's face was pressed hard against the bars; his fingers were hooked around them. His body was almost glowing with a soft film of perspiration.

"John?" he said, struggling to lift his head when his cheek had seemingly fused itself to one of the bars.

"Mmm?" John said dazedly, blinking slowly.

"Would you get your hand out of my hair, you've got the grip of a chimpanzee."

John hastily untangled his fingers from Sherlock's hair, almost bringing a chunk of it with him. He pulled out of Sherlock, suddenly remembering that he was still buried up to the hilt inside of him. He hurried backwards on the bed and accidentally stuck his hand in the bowl of chocolate.

"Oh, great," he grumbled, holding it up.

Sherlock turned to him. He looked perfect. Bedraggled, ravished and used. John loved it. It almost made him hard all over again. "Serves you right," Sherlock said, eyes glinting.

He knelt towards him on the bed. John leant back uncertainly. "What are you doing?"

"Showing you how much I've learnt," Sherlock purred. "Fingers?"

John hesitated, staring at Sherlock's disconcertingly bright eyes. He tentatively held out his fingers. Sherlock took one between his finger and thumb and licked it from bottom to tip, his eyes fixed on John. "Mercury."

He slipped it into his mouth, sucking the chocolate off in a clean stroke of his tongue. When he looked up he had chocolate stuck to his top lip. John almost whimpered. "Venus," Sherlock said in a low voice, taking John's second finger in his and licking it clean. "Earth." He pressed John index finger into his mouth, clumsily lapping up the chocolate from below. It dripped onto his lips and smeared his mouth with velvety brown mess. "Mars," his voice was barely more than a growl. John was definitely getting hard again.

Sherlock breathed against John's thumb, letting out a soft moan against it as he lapped at it. "Saturn." He sucked on it hard. John could feel his mouth was open. He seemed to have lost control of his face.

Sherlock straightened up, sweaty and covered in chocolate with eyes positively glowing at him. "Was that correct, teacher?"

John stared. "What?" he said faintly.

"The solar system?" Sherlock said innocently, cocking his head. "Am I making progress?"

John blinked. "Oh... oh yes... I... Yes. Perfect." He coloured.

Sherlock smirked and slid off the bed. "That's funny..." He plucked John's phone up from the tangle of his clothes at the base of the bed. "The last time I checked Google, Jupiter was next to Mars." A smirk played irresistibly on his lips. "Not Saturn."

John gaped at him. Sherlock shrugged and tossed the phone to him. It landed on the bed with a soft plop.

"You know the sun's going to blow up in about five billion years and obliterate the solar system, right?" Sherlock said in a bored voice. "Why bother to learn about something that isn't even going to exist in the near future?"

"What do you mean near future?" John exclaimed.

Sherlock plucked his shirt from the floor and tugged it on. "Chop chop, John. We don't have all day to laze about."

He wandered out of the room, whistling. John glowered after him, wiping the remainder of the chocolate off on Sherlock's sheets.