It was just another day at 221B Baker Street. John on his computer and Sherlock sharing at the wall, pondering about a weird case.
As many unanswered thoughts and questions ran through Sherlock's mind, he had an interesting thought connected to the case. He stood up from his chair and quietly approached John from behind, extended both his index fingers, and poked John on his sides. John's reaction was immediate as he shot up and yelped.
"What was that for?" John exclaimed while trying to suppress a smile.
"Just testing out one of my theories, John. Interesting that people laugh when you touch or poke them in certain areas." Sherlock pondered aloud.
"Well it's called being ticklish, Sherlock."
"Mind if I further test my theory, John?" Sherlock asked, a hint of amusement in his voice.
"Technically, you already did test your theory. Now if you don't mind, I've got my blog to write."
John was about to sit back down when Sherlock caught hold of his torso and started kneading them lightly.
"Sherlock! Stop that!" John protested, trying to pry Sherlock's hands away from him.
Sherlock only started kneading faster which caused John to fall and buckle in on himself, trying to protect his sides.
"Interesting, but you're not giggling. Deducing from your position, your stomach must be very sensitive." Sherlock said as he skittered his fingers over John's stomach. His theory proved itself as John started laughing, squirming to get away.
"Please d-don't! I can't breathe!"
And at that instance, Sherlock stopped, looking pleased with himself. Just as he was about to stand up, John grabbed Sherlock and tackled him onto the ground.
"John, what are you doing?"
"I'm going to test my own theory on you, Sherlock." John smirked.
"If you're going to tickle me, John, I'll let you know that I'm not ticklish-" Sherlock's speech was cut short by a poke to his ribs.
"Not ticklish, huh?" John grinned as he skittered his fingers over Sherlock's sides and stomach. Sherlock was trying to maintain his composure while trying to push down the giggles bubbling up his system.
"Deducing from your scrunched up shoulders, I'm guessing that your neck is ticklish." John teased, as he jammed his fingers into Sherlock's neck, causing him to start giggling.
"John, stop it!"
"I'm afraid not."
Before Sherlock could react, John dug his fingers into the back of Sherlock's knee, causing the detective to kick his legs in an attempt to get away.
"J-John! Please!"
Sherlock's face was as red as a fire hydrant, so John stopped to let him breathe.
"A detective who's too ticklish, that'll be interesting for my blog." John smiled and looked at his flat mate, who was still giggling, and tested out an actual theory this time.
He lifted the detective's right arm above his head with one hand. John positioned his other free hand right above Sherlock's underarm and without making any contact, wriggled his fingers in the air. Sherlock started laughing as he felt a jolt of that tingly, ticklish sensation shoot through his entire body. It was a weird feeling for him as he was so touch deprived, and he suddenly felt hyper sensitive. It's as if his neck was the key to open the floodgates.
"I can't breathe! Stop it!"
"I'm not even touching you!" John laughed. He felt himself being intoxicated by Sherlock's genuine laughter. It was surprisingly cute and contagious from a person who doesn't laugh that much.
Realizing that they were sidetracking from the case, John eventually stopped, and helped Sherlock back on his feet.
As John turned around to return to his desk, he felt light kneading at the back of his neck. He tried to suppress a laugh while scrunching up his shoulders.
"This is going to be a long day, Sherlock." John grinned as he tried to get payback on his flat mate once more.