“Alright,” Kurt purrs, sashaying his hips as he approaches the bed, drawing things out, taking his time, knowing just how much Blaine wants this and purposefully making him wait. He puts one knee on the bed by Blaine's hip and looks leisurely over the body of his beautiful sub, lying on his back, restrained. Excitement sparks in Blaine's eyes, which are normally a golden-honey color, but turn a dark whiskey when he gets aroused. Blaine's muscles are taut, pulled tight with anticipation, but he keeps a mask of obedient calm firmly fixed in place.

“Since you responded so favorably to electro-shock last time,” Kurt remarks, “and you couldn't seem to get enough of it, I bought us this.”

Kurt lifts up the device he's holding in his hand where Blaine can better see. Blaine's eyes widen, his lips curling in over his teeth to keep his reaction in check. Kurt can see Blaine's body vibrate at the idea of this new toy, with all the places it's connected, of how it's going to feel when it's turned on. Tied securely to the wooden posts of the bed, legs and arms spread and lifted out at an angle, giving him no slack to bend his knees or his elbows, Blaine rolls his ankles and wrists in the restraints – thick leather restraints to keep his body grounded and ensure things don't get out of hand.

“I'll explain the set-up here so you know what we're doing,” Kurt starts. “This controller will be connected to your body in three places.” Kurt runs a hand along Blaine's body, zeroing in on the various plugs and rings he outfitted Blaine with before he left him tied to the bed to go change, have a cup of tea, watch some television…

Kurt can tell by the exquisite trembling in Blaine's tired arms that the suspense has been sublime.

“This anal plug…” Kurt takes his middle finger and pushes the plug that's slid out an inch completely inside Blaine's body, “is way bigger than your other ones. The urethra insert is new for us.” Kurt taps Blaine's cock with a thrum of his four fingers, making sure that it's still rock hard since the moment he slipped the metal rod into Blaine's slit. “And this ring is snugger than I usually buy.” Kurt cups Blaine's testicles where a black rubber ring surrounding a covered wire has been slipped over and firmly hugs them at the base, making them bulge. “But it makes your balls look delicious.” Kurt fondles Blaine as he licks his lips, locking stern blue eyes to his sub's gaze, knowing that a swipe of his tongue over the rim of his mouth is superb torture for Blaine when he's tied down like this. Kurt twists the ring around and Blaine's legs start to shake, matching the tremble in his arms as he struggles not to moan. All three implements – the plug, the insert, and the ring - are connected to white wires that Kurt plugs into the end of the silver instrument in his hand. “I'll just hook these up to this controller and we'll get started. Does that sound good to you, pet?”

“Y-yes, Sir,” Blaine says, nodding so hard his neck cracks.

“The box says unnecessarily powerful,” Kurt comments as he double-checks the connections. “Sounds right up your alley.” Kurt winks and then he waits, watching Blaine's reaction to not getting what he wants right away, his sub's lips parting, breaths panting, his toes curling as he clenches, fighting to keep the plug from slipping out again.

“Do you want me to turn it on, pet?” Kurt coos, hand hovering over the device, one long finger circling the switch. Blaine's eyes follow his Master's finger, waiting for Kurt to turn it on with or without warning.

“Yes, Sir,” Blaine says, wetting his lips.

“Now, what do we say when we want something?” Kurt asks, teasing Blaine, toying with him until he can see him salivate.

“P-please, Sir,” Blaine begs. “Please, Sir. Turn it on.”

“As you wish,” Kurt says, smug in his new investment as he flips the switch.

The machine springs on with a slight buzz as the electrical current engages. Blaine wriggles, his back arching, eyes squeezing shut when the current hits him, and he moans, long and loud and continuous until his voice runs out.

“Oh…oh God,” he mumbles, his back teeth clamping shut. “Nngh…God…”

Kurt grins, intensely proud of himself, an urge to giggle bubbling up inside of him with every twitch of Blaine's muscles as he tries hard not to give in, not to let go and cum before Kurt gives him permission.

Kurt could let Blaine just simmer here, twitching and moaning, while he goes back into the living room to finish the episode of Orange is the New Black he was watching on Netflix, but he's dying as much as his sub to turn up the pressure a bit. He wants to watch Blaine squirm as the force of a stronger current flows from his ass to his balls to his cock, connecting somewhere in the middle, compelling him to cum and taxing the boundaries of his constraint.

“Okay, pet,” Kurt says, his voice faltering a thread with his own anticipation. “I'm going to turn it up a bit past where we had the vibrator set last time and work from there. Are we still green?”

“Green, Sir,” Blaine says, assuring his Dom with confidence that he's fine to move forward. “Sooo green…”

Kurt chuckles at Blaine's impatience and turns the knob.

Like the crack of a whip, Blaine's whole body tenses. His cock throbs, going completely rigid. It bobs and pulses, straining around the insert. He cums up his chest, hitting his neck and beneath his chin, but his face looks twisted, torqued with pain.

“Red! Red! RED!” Blaine screams, yanking hard on the leather restraints.

“Oh my God! Oh my God!” Kurt yelps in surprise. He immediately turns off the machine, unplugging the connections and tossing the controller to the end of the bed like it's a rabid animal. “It's off! It's off! I turned it off!”

Kurt holds his breath and stares at Blaine, face beyond crimson, his left cheek splattered with cum. Blaine holds his breath and stares at Kurt, mouth hanging open, bottom lip quivering, eyes filled with worry. Then all at once, Dom and sub burst out laughing.

“How was that?” Kurt asks between gasping laughs.

“Oh my God!” Blaine says. “It…it started off okay, but that higher setting…” He pauses mid-chuckle and shakes his head. “That was…that was awful!”

“You came like a motherfucker!” Kurt spits out with laughter, which makes Blaine laugh harder, tears leaking from his eyes. “Do you want to try it again?” Kurt asks, wiping Blaine's cheek clean with a tissue while he catches his breath. “Maybe at a lower setting?”

“No!” Blaine says, twisting his head furiously from side to side, bearing down to push the infernal plug out of his ass. “God, no!”

“Alright, alright. Calm down,” Kurt says, putting a hand on Blaine's knee to stop his bucking against the bed so he doesn't accidentally shove it farther in. “I'll get you unplugged.”

Kurt unbuckles the leather restraints from Blaine's ankles, and then pulls the plug gently from his ass. Blaine's laughter winds down in his throat as Kurt works, and he becomes quiet.

“I'm sorry,” Blaine says seriously.

“For what?” Kurt asks, carefully detaching the ring from Blaine's balls. “That you didn't just lie quietly and let me electrocute you?” Kurt sets the ring aside and massages Blaine's legs, relieving the tension from his muscles. “I'm the one who's sorry. I should have tried it out on myself first so I would know how high to go.”

“That's…that's not necessary,” Blaine says, watching Kurt remove the urethra insert and wipe it clean.

“It is if I'm going to keep you safe,” Kurt explains. “Keeping you safe and happy, that's all that matters.” He crawls up the bed and sits by Blaine's side, running his fingers through Blaine's hair and dropping kisses on his forehead, down his cheek, on his neck. “But you said it started off good, right? Maybe with a little endurance training, we can revisit that again.”

“Yes, Sir,” Blaine says, his body relaxing underneath Kurt's hands as his Dom goes back to kneading his knotted muscles. “Yes…I think I'd like that.”

“Good, pet,” Kurt says, nibbling on Blaine's jawline until he laughs. “Why don't we start over?” Kurt rubs the tip of his nose over Blaine's, brushing their lips together, barely touching, almost kissing. “We'll take a bath, I'll wash you down, and then we can do this again with your vibrator. The one you're used to.”

Blaine nods, chasing Kurt's mouth, begging silently for a kiss.

“Or, we could take a shower…and then make love?” Blaine suggests.

“Yeah,” Kurt agrees, gifting Blaine with one light kiss before moving up the bed to untie his wrists. “We can definitely do that.”