Sherlock takes his tasks as the best man pretty seriously. So he (drunkenly) teaches John how the perfect wedding kiss has to be like.
This part is set during the events told by Sherlock in the episode “The Sign Of Three”
“Let me go! Do you even know who I am? I’m Sherlock Holmes, I am smarter than you and your two coworkers combined!”
John sat on the stairs in front of the club and put his face in his hands, both because of nausea and because he didn’t want to see his friend beaten up by security. They wouldn’t let them in, no wonder, they were totally wasted. Sherlock had the perfect idea of getting John drunk to test his limits for the upcoming wedding. The wedding had been the only thing on his mind in the past few weeks, it nearly took up all space in his mind palace.
Finally, Sherlock decided to drop down next to his friend, looking at him with a slight grin. “That’s not gonna work.” John waved off and got up. “It doesn’t matter, let’s keep going. I don’t want these guys changing their minds in terms of beating you up.” Sherlock joined in his step. “They wouldn’t beat me up, they would risk losing their jobs since I’m drunk enough to fall in a deadly way.” John grinned a little bit. “Or maybe they just don’t want to waste their time with you any longer than they have to.”
The doctor watched Sherlock nearly running through the streets, a bit ahead of him. He was checking out every single detail, searching for something interesting to show John. Sherlock turned into even more of a know-it-all when he was drunk, but John found it pretty amusing. He loved watching his friend interact with other people, it always fascinated him how Sherlock never realized how annoying other people found him. Sometimes, he felt bad for him. John was Sherlock’s only real friend, aside from Mycroft and Greg. And Mrs. Hudson, of course.
He wondered if Sherlock could keep on like usual when he would be away more often now. John had to admit, that he almost felt a little insulted when he noticed that Sherlock seemingly had no problem with going on without John always by his side. But he knew that his friend was pretty good at acting and he didn’t want Sherlock doing some stupid things that would get him in trouble again, or worse, killed…again.
“Let’s sit down over here.” Sherlock suddenly stopped in the middle of his step and turned around, pointing at a bench on the side of the street. “The sky looks exceptionally great tonight, we should grasp it.” John raised an eyebrow at his friend’s unusual wording, but he agreed to sit down either way.
It didn’t take long for Sherlock to interrupt the “grasping” with another dialogue with himself. John had no chance to respond since Sherlock always seemed to answer himself faster than John could. The only unusual thing was that he started to giggle in the middle of his sentences every now and then. John had to admit that he found it pretty cute. Sherlock turned into a teenager when he was drunk, interesting. “Do you feel ready for your wedding day?” John looked over at his friend. “Well, can one really feel ready for a day like that?” “Well-” “Aside from you.” John laughed. A few seconds of uncomfortable silence followed.
“What about the kiss?” Sherlock grinned. “What do you mean?” Their eyes met.
“Well, you have to kiss Mary in front of all these people. Nobody would want the kiss to be imperfect in any way. Too long, too short, too intense…” John rolled his eyes. “I have no idea what you mean.”
“Yeah, I thought so. That’s why I’m gonna show you.” “What do you-” Before John could finish his sentence, their lips connected and he felt the adrenaline rushing through his body. He felt like riding the fastest rollercoaster known to mankind. A few moments later, Sherlock slowly pulled away.
“This was the perfect length. Do you know what I mean?” John sat there with an open mouth, staring at his friend in disbelief before grabbing his cheeks. He didn’t think twice before kissing him once again, pressing his lips against Sherlock’s this time. His friend made no effort to pull away. The both of them remained like this for the next few minutes. There he was. Making out with his best man.
Shit, Mary. The wedding. He should stop, he was engaged. And being drunk wasn’t an excuse for the feeling between his legs. But nothing seemed to matter right now. The only thing on his mind was Sherlock. This perfect man, the most fascinating human being John had ever seen. And he was kissing him, pulling him closer by the second, his hands all over his body. John started to notice the people staring at them while walking by and he slowly pulled away, not really wanting to destroy this moment. He felt his cheeks heating up and struggled to maintain eye contact with his friend. Sherlock, for the first time in forever, said nothing. He just seemed to stare into John’s soul with no expression on his face whatsoever. Suddenly, he started to laugh and John nervously joined in. “I didn’t know that you needed this much practice!” “What? Why? Was I that bad?” Sherlock laughed even more and shook his head. The tension seemed to loosen a little bit.
“Do you see this bow on the ground? I am almost sure that it comes from…” Sherlock’s words drifted in and out of John’s mind. He couldn’t concentrate on his surroundings anymore, the man was still stuck in the recent situation. “...and that’s why the bow is the last memory from a date gone wrong.” Sherlock stopped his walk with the end of his story. They both stood in front of Sherlock’s flat now and one exchange of looks confirmed that both of them needed some rest now. Sherlock made some space for John to walk in and as soon as he did, he felt a force pushing him to the wall. His friend stood a few inches in front of him, pinning him against the wall in between his legs. John could feel the both of them trembling as Sherlock pressed his upper body against him. “What are you doing…” John only mumbled since Mrs. Hudson was asleep and he most certainly didn’t want the poor woman to wake up to…this.
Honestly, he didn’t want to know what he did, he wanted to know why he didn’t do it sooner. Alcohol seemed to turn people into different versions of themselves, especially Sherlock. John had never seen him laugh this much. And there it was again, this grin on his face right before he connected their lips to a passionate kiss once again. John’s heart threatened to explode if this was gonna go on any longer. He had never felt this much adrenaline, excitement and confusion, all at once. But even though he was drowing in ecstasy, the rush had a bitter taste to it. Sherlock most certainly wasn’t himself right now, he was completely wasted. And for a second, John wished that his friend would be sober. But he didn’t pull back and they were making out once again, in the stairway of what once was both their home. So many memories were made in this house and if John would have a choice to change something, he wouldn’t. Every single second that he had spent with Sherlock in the last few years was absolutely beautiful, no matter how exhausting it could get. He would never admit it, but Mary couldn’t keep up with the man in his arms. She was smart, beautiful and a great girlfriend, but nevertheless, sometimes John would lay awake at night, thinking about his consulting detective. The strange man with the even stranger habits that he grew to love so much that he risked his marriage right now.
And god, he did risk his marriage.
A chuckle pulled the both of them out of their moment back into reality. John glanced to the side and looked into the warm face of Mrs. Hudson. She was smiling while putting her hands together as if she had been waiting for this moment for years. “Mrs. Hudson, I’m so sorry for waking you up. We were just…” She shut him up with a little wave. “No need to apologize, John. It is nice to see you again.” Sherlock didn’t waste any more time on this uncomfortable moment, he grabbed his friend’s hand and pulled him upstairs. As he was stumbling up the stairway, John looked back at his old housekeeper once again. She winked.
“See you soon, John. I’m looking forward to the wedding!”