please forgive me any mistakes, english isn't my first language, but feel nevertheless free to point them out XD
The case Sherlock was working on was far from being solved. Although he should have enough information to do so there was no progress. Sherlock couldn't think of the right conclusion that fitted all the facts. All possibilities he thought of left something that didn't fit the facts. So Sherlock's mood wasn't the best and John had gone out to buy something sweet to eat.
Sherlock noticed that he was out of nicotine patches, which was pretty bad in his current state, but he was too lazy to text John about this problem. He decided that he would wait until the doctor would come back and then ask him to buy him some.
An hour had passed when he heard John coming upstairs, and he bent his head a little when the door opened so that he could look at John.
"John could you get me some nicotine patches?" he saw John's mouth twitch. Maybe he should have texted him after all, but his mobile was in his coat. It never crossed his mind to go and buy them himself.
"No Sherlock. You could have texted me" was the annoyed reply he got. It should have occurred to him that it was not likely for John to go out again just to buy Sherlock nicotine patches. Even more so because it wasn't the first time that Sherlock asked John to buy him something right after the doctor came back from shopping.
"But I need them to solve the case!"
"If you want something to think better, then eat something sweet. As a doctor I tell you that your brain needs some sugar to work properly" he said with a sight because he knew that Sherlocks logic was sometimes, well twisted.
"John, you know fair well that I don't eat while working on a case" before he could begin to tell why wouldn't eat anything John went into the kitchen, ignoring Sherlocks complaint. After a while he returned with tea and a cinnamon roll, placing both of them on the couch table.
"Here, eat" John ordered him
"I wouldn't say no to the tea, but you can have the cinnamon roll for yourself" Sometimes, well most of the time Sherlock could be really stubborn. John had observed his flat mates face carefully, a habit he had developed since he started living with Sherlock. And he could see that he actually wanted to eat the roll, but his previous statement, about eating slowing down his ability to think, wouldn't let him. Would it hurt his pride so badly if eating something would help him think better? With a sight the doctor took the cinnamon roll and put it back into the kitchen because Sherlock would clearly not eat it. He made another cup of tea for himself before settling in his armchair.
After a few minutes of silence, Sherlock starts to complain about the nicotine patches again, acting like a five-year old and the good doctor sighs, telling Sherlock to go and get it himself for what felt like the tenth time, resulting in Sherlock not speaking with his flat mate anymore and started pouting, again. John really felt like dealing with a child.
An hour passed in silence and John decided to try making Sherlock eat something again. Maybe he was less stubborn now. As he was about to head into the kitchen to fetch the cinnamon roll he caught a glance of Sherlocks expression and knew immediately that the roll would develop a life of its own if John wouldn't eat it himself. Returning to the living room he sat back down and began to eat the cinnamon roll.
Sherlock watched John eating, thinking that maybe, just maybe the good doctor wasn't so wrong and his brain would work better with some sugar. His eyes darted to John's lips before he could stop himself. Of course he wouldn't eat anything. First would it slow down his ability to think and the other point was that John definitely would not get him any nicotine patches, but most importantly; he wouldn't give John the satisfaction of being right. But he wasn't the only consulting detective in the world for nothing. He had already a solution for all of his problems and chances were good that John would even get his nicotine patches. Sherlock had to suppress a smirk at his brilliance. Well, he wasn't completely sure that this would go the way he wanted it to because sometimes John's reactions still surprised him.
Getting up from his comfortable position he went over to John stopping right in front of him. The doctor looked up from his plate, raising an eyebrow he silently asked what Sherlock wanted. When Sherlock didn't answer he just continued eating, already used to his flat mates intense staring, but John had suddenly trouble swallowing. Something was different about this stare, but he couldn't quite say what it was. Thinking a few moments longer he realized what it was. Normally Sherlock would make eye-contact, but when John looked up to Sherlock again he still didn't meet his gaze. Instead he continued to look at…his mouth? No, that was absurd. The corner of his mouth twitched at this silly thought. Knowing Sherlock it was more likely that he was so absorbed in his own thoughts that Sherlock simply forgot that he was staring at John.
Sherlock eyes snapped away from John's mouth - as well as the crumbs that were at the corner of his mouth – to meet the gaze of two hazel eyes and moved back to the doctors mouth a few seconds later. Sherlock bent down and licked over John's mouth –and the crumbs away- then began to move his lips slowly against it. He moved his hands to hold John's face in place and bend further down to deepen the kiss. John opened his mouth a bit and Sherlocks tongue darted in, eagerly exploring it. He could taste cinnamon and the sweetness of sugar. John moaned underneath him, hands tangled in his dark curls. Sherlock began to feel warmth seep through his whole body, causing his mind to forget his original plan and he began to attack John's mouth hungrily. When John started to kiss back with just as much need Sherlock didn't really care anymore if he would get his nicotine patches or not because kissing John stimulated his brain better than the patches ever could.