A/N Hey My Lovelies!!! So a while ago I wrote the first half of this one and a lot of you wanted to see the rest and I finally finished it!!!!! SMUT WARNING!!!!!! Captain Watson makes an appearance in this!! (Lowkey love Captain Watson NGL) Hope you like it!!! Enjoy<3

When John made his way up the stairs, almost a half-hour had passed since Sherlock had scurried off to shower. John had decided to make the detective wait an extra ten minutes, to remind him that they were playing by his rules, not Sherlock's.

The detective was sitting on the edge of the bed, looking bored until he noticed John. The former soldier noticed the change as soon as Sherlock's eyes landed on him. The taller man's spine straightened and his eyes widened. John smirked and stepped closer, coming to stand just before Sherlock and dug his fingers into the younger man's curls. He tugged Sherlock's head back and hummed at the gasp he pulled from the man's throat.

"Before we start, I'm going to lay down some ground rules. Okay?" John made sure to keep his voice firm, but not overly dominant yet, just strong enough to keep Sherlock's attention. He felt the detective nod slightly and tightened his grip in his curls, pulling another gasp from him. "Okay?" He asked again, hardening his voice.

"Y-Yes Sir."

"Good. Now, you do what I say, when I say it. We will discuss safe words later, but for now we will use the traffic light system. Are you familiar with that system Sherlock?" The shock in Sherlock's eyes sent a thrill of glee through John's body. Not all tea and jumpers, am I? "No, this is not my first time playing like this, but I can tell it's yours. I need you to answer the question Love, are you familiar with the traffic light system?"

"N-No, John- I-I mean, no Sir."

"Good boy. Green means keep going, yellow means slow down or I need a break, Red means stop." John moved his hand from Sherlock's hair and gently gripped his chin. "Do you understand Sherlock? If you say red, I will stop everything and back down."

"I understand Sir."

"Give me a color then." Sherlock was coming out of the haze of arousal enough to meet John's eyes with a semblance of awareness.

"Green, Sir." John grinned and leaned down, roughly kissing the detective and pulling a shocked moan from the man.

"Perfect." He growled against Sherlock's lips before stepping back, standing at attention and sending Sherlock a look that made the younger man's figure straighten instantly. "On your knees Soldier." His voice dropped easily back into one of military command and Sherlock obeyed instantly, sliding off the bed and to his knees.

It must have been an insanely erotic sight, Sherlock naked and kneeling before the former soldier, who was still in his fatigues. He reached for Sherlock's chin, cupping his face and running the pad of his thumb over Sherlock's lips. He had dreamed about those lips, about kissing them, about what they would look like stretched around him. He pressed his thumb into Sherlock's mouth and used the grip to pull the man higher up.

"Suck me." He commanded, holding Sherlock's eyes firmly, just long enough to make the man whimper and squirm before releasing him. Sherlock eyed his crotch hungrily but seemed to hesitate, chewing at his bottom lip. John felt a flare of concern at the hesitation and instantly softened. "Give me a color Sherlock." He whispered, stroking Sherlock's cheekbones gently. The younger man looked up at him, dazed and slightly confused.

"Green John, nothing changed. I was waiting for your command." John chuckled and pulled Sherlock up to meet his lips in a tender kiss.

"There's a good soldier." His kept his tone soft at first, nothing more than a gentle praise. Then he released Sherlock's jaw and returned to attention. "Now, do as your told and suck your commanding officer. I want to feel that gorgeous mouth." Sherlock scrambled to obey, tugging the zip and buttons of John's fatigues open and mouthing at the cotton pants cover his swollen erection.

John dropped his head back and groaned when Sherlock finally took him in his mouth. That blasted tongue wasn't just skilled at words apparently.

He let Sherlock continue sucking for a few minutes before he had to push the submissive man away and grip the base of his erection tightly to stop himself from finishing there and then. He reached down and gripped Sherlock by the shoulders and hauled him up, throwing him backwards onto the bed.

He reached into his bedside drawer and pulled out a bottle of personal lubricant, tossing it to the detective and moving to sit in the chair in the corner of his room. He leaned back and crossed his arms, grinning at the confusion on Sherlock's face.

"Go on then, prepare yourself for me." Sherlock's eyes shot wide and he glanced between the bottle and John, looking terrified and uncertain. John leaned forward, sensing that the man was struggling.

"Y-Yellow." Sherlock stumbled over his words. John stood slowly, walking back to the bed and sitting next to his detective. "I-I'm sorry-"

"Never apologize for not doing something you don't want to do. What's wrong? You have to talk to me." Sherlock lowered his head and blushed, starting to close himself off. John gently took his chin in his hand and pressed soft kisses to Sherlock's lips and nose. "We can stop playing if you want, if it's too much." Sherlock pulled back, shaking his head desperately.

"N-No! I-I just- I've never- I-I don't know what to do." John calmed him with a kiss. "I don't want this to end." Sherlock mumbled against John's lips, pulling a soft smile from John. He pulled away and studied Sherlock's eyes, reading nothing but need and truth in them.

"Are you sure? We don't have to stop this, but we don't have to play anymore." Sherlock shook his head, shifting and crawling onto John's lap, pressing kisses and gentle nips to his neck and shoulders.

"No, please, I want to keep playing. I'm sorry Captain Watson. Please don't stop, I promise I'll be a good soldier."

"Give me a color Sherlock."

"Green Sir." John grinned dangerously and lifted Sherlock from the bed, turning around and depositing him onto the mattress. The normally stoic detective yelped as he fell, but the sound soon changed to a gasp as John ran his hand along Sherlock's chest, teasing his nipples as he went. He stopped his hand at Sherlock's hip, not touching the other man's erection yet.

"Hands and knees Soldier." Sherlock scrambled to obey, quivering under John's touch. "I'm going to prepare you myself this time, but pay attention soldier, because next time we play I'll expect you to do it yourself." Sherlock whined and nodded, jolting in shock when John brought his hand down in a firm slap against the detective's arse. "When I say something, I expect a response Soldier!"

"Y-Yes Sir!" John grinned and grabbed the lubricant, slicking his fingers and pressing one into Sherlock without warning. Sherlock gasped and keened at the action, but pressed back against John. He worked Sherlock open as quickly as he could, taking care to avoid the man's prostate, just keeping him on that edge of not enough and too much. "C-Captain- Captain please- I-I need-" John pressed soothing kisses to Sherlock's back as he slipped his fingers out, grabbing a condom from the drawer and rolling it on.

"You've been such a good soldier, obeying my every command." He slicked his erection, hissing at the contact and lined himself up to Sherlock's entrance. "I have one more command for you though." He whispered, pressing in just enough so that the head of his member breeched Sherlock. He felt Sherlock's entire body shudder against him.

"Y-Yes Sir?"

"You are not to come until I say, understand Soldier?" Sherlock tensed slightly but then went boneless against John. "Give me a color Soldier."

"Green Sir! Please Captain- please-" John slammed into Sherlock's body before the genius could finish begging, changing his words from a plea to a loud moan.

John pounded into Sherlock's body, reveling in the sounds his rough thrusts pushed from the detective's lungs. He wrapped one of his arms around Sherlock's chest and hauled him up and back against his own, biting down on his neck and leaving a harsh purple mark.

The change in angle caused his member to brush against Sherlock's prostate with every thrust, turning the genius's moans and whimpers to cries of lust and need.

When John felt his own orgasm cresting, he reached around and gripped Sherlock's member, stroking him in time with his hips.

"Come for me Soldier." He growled in Sherlock's ear as the detective tried to double over, John keeping a tight grip across his chest so he could watch as Sherlock finally came. He watched as the man spilled over his chest and stomach as well as John's hand.

Watching Sherlock come apart was enough to drive John over the edge of his own release, spilling into the condom and biting down on Sherlock's shoulder.

Once they could function, John hauled Sherlock out of bed and down to the shower to clean up. They showered together, sharing soft kisses and tender touches.

When they were curled up together on the sofa later that night, eating leftover takeaway and stealing soft kisses late into the night. John reached behind the sofa cushions and pulled out an old, ratty envelope and pressed it into Sherlock's hands, blushing lightly.

John felt the detective tense against him when he opened the envelope, sorting through the various old pictures John had saved from his army days.

When he reached the bottom of the stack, the pictures were new, recent ones John had taken after discovering Sherlock's soldier kink. Some where simple shots of him in uniform, then there was one, tucked in the middle of the stack, of him in his trousers, a simple white vest that he had snagged between his teeth. His had was wrapped around his member and John knew the instant that Sherlock saw that photo.

"J-John-"

"Just a little something to fuel your wank fantasies." John winked and stood, sauntering into Sherlock's room. He heard Sherlock's whine as he pulled his shirt off and tossed it back to the stunned detective.