Written for this kinkmeme prompt: "Sherlock is a marine biologist. John specialises in octopi. They bond over ink and tentacles. Also suckers."
There's a severe lack of porn in this fic. It's really quite embarrassingly tame.
Also, there's a good chance I may have made some scientific errors in this.
The study of cephalopods is a branch of malacology known as teuthology.
When John Watson is older, he'll learn the art of seduction - how to be harmless and confident, intelligent and self-deprecating, suave and yet unpretentious all at the same time. He'll be able to boast of having relations with people on three continents.
At fifteen, it seems he'll be lucky to have relations with anyone at all.
"You know," he says. "The blue-ringed octopus is known to be rather enthusiastic during mating season. The male attempts to, er, copulate with other members of its species regardless of sex. It's also one of the most deadly-"
The pretty blonde is gone before he finishes the sentence.
"Oh, Johnny," Harry says, slinging an arm around his shoulder. "You're never going to get a girlfriend like that."
Regardless of what his sister thinks of his interests, "Hello, My name is John Watson and I'm a marine biologist," turns out to be the best pick-up line he's ever tried.
John walks out of the interview at the aquarium with his name on the shortlist of candidates and the interviewer's phone number in his pocket.
Around the time he reaches the South Pacific-themed displays, John catches sight of dark curls and mother-of-pearl eyes and decides that that phone number is going in the first trash can he sees.
The tall man is staring intently into a glass case. He looks very pale in the aquarium's dim light, almost ghostly compared to the rainbow of anemone and fluorescent fish behind the glass.
"Crown of thorns starfish," John says, stepping closer and nodding at the spiny animal in question. "Second largest sea star in the world. And that's a southern blue-ringed octopus, one of the deadliest creatures in the ocean."
"Yes," the man says. "Isn't it lovely?" He smiles slightly and reaches a hand out as though to touch the glass. "Histamine, taurine, acetylcholine, and dopamine, among others. But mostly tetrodotoxin."
John realizes suddenly that there may be something wrong with him, as his first response if to find that the hottest thing anyone's ever said to him in his life.
"Hello," he says, sounding a bit more shell-shocked than he had intended. "My name's John Watson. Would you like to go out for dinner sometime?"
They go out for seafood, just because.
Sherlock looks at John over braised swordfish and white wine and tells him about the research he's doing on venomous sea creatures.
"I need a research assistant," he says. John's eyes follow the long lines of his fingers as they curl around the stem of the wineglass. "Someone who's not afraid of handling the specimens."
Their eyes meet.
"Could be dangerous."
John just grins.
He loves when Sherlock visits him at work and John gets to pull him down and kiss him while rays and eels and angelfish float heedlessly along behind them.
"Hapalochlaena lunulata," John says as the colorful octopus crawls over Sherlock's gloved hands. The little cephalopod twines a tentacle around one of his slender fingers. "Don't let him crawl up your arm."
"I won't," Sherlock murmurs.
The greater blue-ringed octopus is a new arrival at the aquarium, and John couldn't resist letting Sherlock have a sneak preview.
"I have a research opportunity in Australia," Sherlock says, gently sitting the creature at the bottom of the tank and removing his hands from the water.
He strips off his gloves slowly. "I bought two plane tickets."
It's turning to summer on the far side of the world. John rubs sun lotion on Sherlock's pale shoulders on the days he can tempt him out of the marine institute and onto the beach.
They lay next to each other near the surreal blue waters and regret nothing.