All day, Merlin can feel his tattoo burn. It knows, because Merlin knows, that Arthur won't be home tonight. Merlin rubs at his shoulder and scratches his back against the corner of his door. He knows he shouldn't, but it's really the least of the things he shouldn't do today.
No matter how hard he tries to stop himself, he knows he's going to do them anyway. He's not sure he has any choice. Months of quick showers, years of Arthur's tongue obsessively laving the spread of inky tentacles across Merlin's chest and back, and every time the wetness stirred it just enough torment Merlin with its hunger.
At lunchtime, he goes into the lavatory and pulls the top buttons of his shirt open. He runs his hand under the warm tap and then runs it over his chest and shoulder where the ink twines around his heart. An immediate shiver runs through him. The skin under his hand ripples with anger and promise.
Merlin returns to his desk to find a missed call from Arthur. He's desperate and hesitant to call back and hear Arthur's voice.
“Ah, there you are,” Arthur says when Merlin finally phones. “I thought you ran off to have yourself a little holiday as soon as I left you unsupervised.”
“Had to go to the loo,” Merlin retorts, looking down to make sure his shirt was rebuttoned properly. “The wild party’s not until tonight.”
“A likely story,” Arthur scoffs, the fondness in his voice seeping like syrup into Merlin’s ear, soothing the itch. “So what are your wild plans for the evening?”
“A nice, long bath.” Just saying the words feels audacious. As his cock responds, Merlin can’t help pushing into the danger. “Should be peaceful without you wandering in to lick the suckers off my tattoo.”
Arthur chuckles at that. “You’ve only yourself to blame. What possessed you to get an octopus tattooed over half your body, I’ll never know.”
Merlin can remember exactly what had possessed him all those years ago—a pair of piercing blue eyes and a matching smirk through the window of the tattoo shop. He’d walked in as though hypnotized.
The young artist with the ink-black curls had looked him over and pulled the neck of Merlin’s henley down to expose his shoulder. “If you let me put anything I want on your skin,” he said without preamble, “I’ll suck you off when we’re done.”
“I’ve no money.” Looking at the other man’s plush lips, Merlin had never felt the despair of the penniless university student so keenly.
“Never mind that,” the artist said and led him to the back of the empty shop.
The next hours remained a blur in Merlin’s memory. He remembered the never-ending buzz of the needle and the escalating burn as it went over and over and then somehow through his skin, like the needle was pushing the ink straight through his muscle into the bone. He remembered gritting his teeth against the pain and the arousal that bulged out of his jeans. The tattooist gave him no rest, but when it was over, he gave Merlin the most glorious, luxurious blow job he had ever experienced.
“Don’t get it wet for a week,” he admonished as he smoothed the gauze over the expanse of the new tattoo. His touch now had a tenderness that matched the tenderness of Merlin's skin.
Merlin nodded with a daft grin and wandered, fluffy-headed, out into the daylight. He was not sure it was even the same day. The glow in his chest and belly didn't care.
A week later, he finally took the bandages off so he could sneak into Arthur's dad's hot tub while the Pendragons were on holiday. When he went back, screaming, to the tattoo shop, he found nothing but a pizza place where the shop had been.
By the time he gets home, Merlin has been hard for most of the day, shirt untucked to hide the strain in his trousers. He doesn't bother turning on the lights or looking at the day's post. He goes straight upstairs and runs the bath.
When the first splash of water hits the bottom of the tub, Merlin gasps as his left shoulder wrenches his back into an arch. He feels the magic under his skin. It wants out. "Oh, not yet," he mumbles, though he knows he shouldn't tease it. "You can't do anything yet."
Merlin forces himself to undo his shirt methodically, even though his fingers tremble and slip on the buttons. He removes his trousers and briefs the same way, and forces himself to fold everything and hang it on the towel hooks behind the door. The water is getting higher, but he is the one choosing this; he is the one still in control.
He waits until the water is as hot as he can stand. Heat is a soporific; his companion prefers the chill of its dream sea. As he bends over the steam, the ache in his shoulder settles.
“That’s better,” he murmurs, though it’s not really better at all, because now all he can feel is his cock.
He steps into the wide, deep tub Arthur had installed because Merlin wanted it, God help him. The hot water sloshes around his knees and then slips silken around his arse, his balls, and his rigid dick. It comes up to his chest and tickles at the bottom of the tattoo. The water shivers and he feels the first squirm in the tips of the tentacles.
Merlin cups his palm and drizzles a handful of water over his shoulder, letting it run down his chest and back, as gentle a greeting as is ever possible between them. Then he slides down into the water until he submerges up to his neck.
He closes his eyes so he won't have to watch the ink lifting from his skin and taking form. He can feel it nonetheless, the weight in his chest as it grows and grows and grows.
"You're like a damn sea monkey, you know that, right?" he whispers.
An arm slithers across his throat and clamps around his jaw to silence him. The rest of the arms slither around his body, prodding for a grip on his flesh.
He knows what it wants: to turn him over, face down in the water, so it can get to the part of him it likes best. By the end of the night, he’ll probably allow it, when he craves the intensity enough to disregard the danger.
But for now, he bends his knees and braces them against the side of the tub. That makes space for two of the growing arms to twine around his legs. It forces his spine to arch backwards. More arms wrap around his ribs, encasing his torso, pinning his arms to his sides while the expanding mass of the creature covers him.
The arms shift, undulate, tasting his skin with dozens of tiny suckers as the arms grow longer and wrap around him further. He inhales as each flicker of suction arouses his skin. This was why Arthur must be away at least for the weekend before Merlin will risk this; Merlin could never explain the dozens of red circles that will soon cover the whole of his body.
The bulk of it presses Merlin’s erection down into his belly. He groans without thinking at the pressure. Instantly, the arms tighten around him, suckers digging into his flesh when instinct drives him to thrash in their grip.
He keeps thrashing and laughs as it coils around him. He refuses to open his eyes and look at it, but he knows it has grown as large as it can within the confinement of the tub. It knows it as well as he does and lets out a screech of frustration.
“Maybe someday I’ll take you to a big pool,” Merlin lies with a gasp. “Oh, you like that, do you? Olympic sized, yeah? Or a lake.”
Or the ocean. That will be the only way he can ever be rid of it. If he even can. If he ever would.
It trills more softly and rewards him for his lies. Suckers clamp onto the tender skin of his inner thighs, wrenching them apart. Then one arm untangles from his leg and probes between them.
This entry is nothing like when Arthur’s cock enters him. The tip of it wriggles into his arse, inadvertently teasing his rim so that his hole contracts around it. Then the bulk of the arm pushes in behind it, scraping and stretching him.
Merlin grits his teeth against the discomfort because he knows what will follow. He writhes through it until the arm flattens out inside him, matching the curves of his passage. A cluster of suckers attach to his prostate, and a moment later Merlin stills into the most exquisite pleasure he has ever known.
It still surprises him, every time.
After that, he is lost. It can do with him as it pleases. His head lolls to the side, weakened from ecstasy.
Later, it hisses, and he rouses with a sharp breath. The tub level has gotten dangerously low after they flooded the rest of the bathroom in their mating struggle.
With his free foot, Merlin fumbles for the faucet. He nudges the tap toward cold and lets the water run.