Disclaimer: The brilliant characters belong solely to J.K. Rowling. The plot and typos are my own. No profit is being made.
Written For: Kink!Night on Severus Sighs in honor of Harry Potter's birthday (July 31).
Kinks: Light Bondage, Electro-Stimulation, Rimming
Warning: This piece is NC-17 and contains explicit slash/sex.

~ Undercurrent ~

"What is that?" Harry asked in what he hoped was a confident-sounding tone.

While it was true Severus had always been creative in the past with birthday presents – particularly the variety that occurred in their private bedchamber – something about the situation Harry now found himself in stirred up an excited nervousness in the pit of his stomach. He gulped as Severus approached the bed with a black, plastic carrying case.

Severus looked at Harry, who was struggling almost imperceptibly against the bonds around his wrists, and offered a self-satisfied grin in lieu of an immediate answer. As he sat down on the edge of the bed where Harry lay, he drifted a hand lazily up a bare calf.

"Surely, Mr. Potter, I do not need to explain the finer points of electro-stimulation… do I?" Severus drawled silkily. Pausing for effect, he eyed his younger lover, trying not to chuckle at the expression on Harry's face.

"Indeed, an explanation will not suffice. Perhaps a demonstration, then?"

Harry felt his eyes widen and his pulse thrum insistently against his chest. Electro-what? he thought wildly to himself. Questions barraged his mind, each one as ridiculous as the next, but he could not brave voicing them.

Severus crawled up onto the bed and set the plastic case next to him. Spreading Harry's legs, he knelt between them and smoothed his warm, long-fingered hands along the outsides of Harry's thighs. Leaning down over the toned body below him, Severus placed a trail of slow kisses down Harry's chest and abdomen, nipping gently at the nubs of Harry's nipples before assuaging the gesture with a swirl of his tongue.

Harry inhaled swiftly, feeling his body arch under the long-familiar touch.

As Severus sat back up, he smoothed his hands down the length of Harry's body and drew the anxious green stare into his own smoldering black one. Harry swallowed thickly but understood: over the years together, they had developed a kind of unspoken communication. He could almost hear the deep, velvety timbre of Severus' voice speaking in his mind.

Relax, my Harry. You're safe.

Harry slowly let out the breath he had been holding in his lungs, the tension beginning to ease across his naked body. Focusing his attention on Severus instead – who was busying himself with the contents of the plastic case – he took in the lithe form of his partner of six years: the black trousers; the crisp, white button-down shirt with sleeves rolled back to his forearms; the ebony curtain of hair presently shielding most of his face.

"So beautiful…" Harry whispered, tugging instinctively at the bonds around his wrists. They were taut but comfortable. However, with his arms drawn up over his head, he could not reach down and touch his lover as he was wont to do. Both the urge and the restriction were blissfully torturous and he mewled desperately just as Severus turned back around to face him, an eyebrow arched as though to say, really…

They grinned at each other for a moment before Severus spoke.

"Electro-stimulation is the application of a low frequency, electrical current to the body. If done correctly, it should excite your nerves and intensify your orgasms."

Harry was about to comment that Severus sounded like a textbook until the reality of that last word lodged in his awareness. "Orgasms?" he spluttered, drawing out the trailing 's.'

Severus merely smirked in response as he coated a short, blunt-tipped metal object with a thick gel-like substance. Harry watched curiously, feeling himself gulp in anticipation.

"What, no magic tonight?" he asked.

Severus shook his head. "No. It is not advisable to mix magic and electricity."

Harry wondered if he should be thankful he only had one birthday a year. Just then, he felt a cold object press against his anus, making him gasp loudly.

"Relax, Harry. This won't hurt." As he spoke, Severus smoothed his left hand soothingly along Harry's arse as his right hand pressed the rigid implement into the tight ring of muscle.

Harry gathered his lower lip into his mouth at the intrusion – as promised, it was not painful – just jarringly cold and strange.

"I will apply electrical current now. It will start at the lowest setting and gradually increase so that it properly prepares you for me."

"Wha–?" Harry started to say but inhaled sharply at the onset of a tingling sensation in his anus. "Oh!" he replied, a bit more wild-eyed than he would have liked to appear.

Severus merely grinned and adjusted the knobs on the device in his hand, stopping only when he could tell Harry was acclimating to the sensation. Setting it aside, he grabbed a silver ring and leaned forward to take Harry's cock in his hand. Coaxing it to life languidly – which, with Harry, never took long – he slid the ring around the shaft and positioned it near the base.

Harry moaned softly at both the stroking and the new implement and watched Severus intently while trying not to squirm too much at the sensation tingling in his arse. He noted that the cock ring was not very snug and wondered if it was similar to the kind that withheld orgasms. Turns out he didn't have to wonder for long.

Severus reached over and attached two cords to the ring and picked up the device with the knobs again. Eyeing Harry in a satisfied manner, he answered the query in Harry's gaze.

"If I am correct in my estimation," he said softly – if not a bit dangerously, "this should drive you wild."

Harry swallowed hard and braced himself – but for what, he did not know. Then, as Severus turned a knob slowly, Harry felt a tiny jolt of electricity shoot up the length of his cock at the same time it spread into the area around its base.

"Ohhh…" Harry moaned, closing his eyes tightly. He was starting to understand why Severus had insisted on tying him to the bed before giving him his birthday gift – the fact that he couldn't move or relieve himself in any way was indeed driving him wild, as were the tandem sensations flooding his lower body with tingly, prickly pleasure.

As he reopened his eyes, he took in the hungry expression on Severus' face for only a moment before his lover's lips engulfed the head of his cock, the warm heat and wetness there nearly sending him over the edge already.

"Severussss…" he ground out, his fingernails digging into the bonds at his wrists. He bucked his hips up into Severus' mouth as he was swallowed whole.

But Severus was unrelenting. He closed his lips around Harry's cock and added just the right amount of suction and tongue as he busied his hands with cooperative activities: his right, pinching and tweaking Harry's nipples; his left, gently nudging the anal implement in and out, ensuring the metal sides made contact with as much of Harry's anus as possible.

Harry thought he might scream, or pass out, but instead he came forcefully into Severus' mouth, the hot pulses of semen mirroring the pulses of electrical current in his body. He was gasping for air as his eyes nearly rolled back into his head; his forehead, sweaty with exertion; his body, flush with arousal. As he fought to regain his breathing, he tugged harder at the bonds and whimpered, wanting to touch and feel his lover.

Seeming to understand this, Severus wiped his mouth with the back of his hand and swallowed before leaning down to crush his lips against Harry's, kissing him with fervent intensity, sliding his tongue across younger lips until he was eagerly accepted inside. They sighed in unison, tasting and teasing each other with their mouths.

After a few moments, though, Severus pulled back – much to the dismay of Harry, as evidenced by the pout that graced his handsome features.

"If you recall, Harry, I did say orgasms. I'm not done with you yet."

Harry grinned drowsily but noticed his cock had not yet recovered from the first round. Severus seemed to catch the glance as well and remarked on it.

"Do not fret," Severus smirked as he picked up the device with the knobs. Harry felt his heart race in his chest, but this time it was out of excitement, he realized.

"What is that thing?" Harry managed.

"The control unit. It is connected to both implements by way of these leads," he answered, lifting one of the cords with his index finger. At that, he turned one of the knobs further around clockwise and Harry felt an increased surge of current around his cock.

"Ahhhh!" he gasped, his eyes widening at the unexpectedly arousing effect the increased intensity had. It was alternatively pleasurable and painful – just the right mix.

Severus set the unit aside again and reached down to grasp the implement in Harry's anus. He pulled it out slowly – deliciously slow, Harry noted – and moved it in a small circular fashion as he went, once again letting it zap and tease the skin around Harry's entrance.

Harry couldn't help but squirm and wiggle his hips, knowing what he wanted next and anticipating he was about to get exactly that.

"Please…" Harry breathed as the implement was removed completely, leaving a tingling and buzzed sensation around his arse in its absence. He looked up at Severus then, eyes blazing with need. Birthday present plan or not, Harry wanted to be fucked. Hard.

Severus' eyes seemed to register the request immediately and he acknowledged it with a sardonic arch of his eyebrow. Pursing his lips, he feigned a thoughtful expression.

"Hmm, but I'm not sure you're ready for me yet, Harry."

Harry made a soft whining noise as he tried to wrap his legs around Severus.

Severus reached down and pinned Harry's legs to the bed instead.

"Tut tut," he chastised with a smirk. "So impatient, Mr. Potter. Let's see if I prepared you enough first."

With that, he leaned down and slid his tongue into the cleft of Harry's arse, dragging it slowly along the outer rim of his anus, tracing the opening. And then he dipped it inside, flicking it against the interior walls before closing his lips and dragging his teeth lightly against the muscled surface.

"Oh fuckkk!" Harry shouted, trying to grind his hips against Severus' ministrations but finding himself mostly immobile now that his legs were pinned down too. "Just fuck me!"

"Your wish is my command," Severus furnished lazily as he sat back up. Quickly summoning his bottle of homemade lubricant, he dribbled a bit in his hand and coated his now painfully erect cock with it – noting with pleasure that Harry was fully aroused again, too.

Pulling Harry's hips up a bit, he positioned his cock near Harry's entrance but then paused a moment. Picking up the control unit, Severus adjusted the setting on the cock ring so the electrical current changed from a solid on pattern to a pulsating rhythm. Satisfied with the shocked gasp it elicited from Harry, he set the unit aside and grabbed Harry's hips firmly.

"Happy birthday, Harry," Severus offered with a grin.

"Why are you telling me that already? We're not done yet!" Harry panted, a trace of panic in his voice at the thought that Severus would leave him in this state.

"Because by the time I'm done fucking you, Harry, you won't even be coherent enough to remember your own name, let alone that this was your birthday present. I just wanted to be preemptive."

If he could have bottled the look on Harry's face right then, Severus would have – he would never tire of that impassioned, lustful, wanton expression Harry so generously gave.

And with that, Severus thrust his hips forward in one smooth motion and buried his cock to the hilt inside Harry. The implement had done its job well, indeed.

"Uhhhh…!" Harry cried out, the groan sounding as though it was wrenched deep from within his throat. "Oh God… fuck…yes…!" he continued with each subsequent thrust. But as he tried to wrap his legs around Severus' lower back to gain some traction, he felt long-fingered hands maneuvering his legs to press up against his own chest instead, followed shortly by the weight of Severus' warm body on top of them.

Harry barely had time to register the position when he felt Severus pull out nearly all the way and then slam back into him, repeating it a few times while he adjusted his angle. And when he found the sweet spot, Harry nearly screamed at the searing pleasure – his arse was still buzzing from the electrical preparation, his prostate was singing with every thrust from Severus, and his cock was throbbing with the pulsing stimulation from the metal ring circling it. He wanted to moan or yell or something but he was so lost in a sexual haze he could barely muster a sound.

Severus watched Harry's eyes close and his mouth slacken and knew that was his cue. Overstimulation never looked so good. Indeed, what better than to add to it?

Positioning himself so he could brace his weight on a combination of one hand and Harry's legs, he grabbed Harry's cock with his other hand and started to stroke him in tune to his thrusts, gradually increasing the tempo as he went, relishing all the sensations – and the visuals.

As the warmth spread from his pelvis to his cock, Severus knew his own orgasm approached quickly. Harry was so delirious with pleasure he was already incoherent, but if the flush in his skin and the rapid increase in his breathing was any indication, he was close too.

Letting go and melding into the moment, Severus closed his eyes and threw his head back, releasing a long, grinding groan just as white flashes of light burst behind his eyelids; his breath, held briefly in his lungs before being expelled loudly; his thrusting, slower now, deliberately soaking in the final wave of intense pleasure. As this was all happening, he became vaguely aware of a hot, sticky liquid dripping down his hand from the head of Harry's cock.

Taking a deep breath, he opened his eyes and looked down at Harry. Sure enough, he had passed out. His breathing was more even than Severus' and his expression was serene but reminiscent of being utterly debauched.

Content – and a little smug – Severus leaned down over his lover and kissed him. Without saying a word, he still communicated what he wanted.

Happy birthday, my Harry.