The first time the words Nice arse coursed through his mind in association with Harry Potter, Severus Snape gripped his lectern furiously until his classroom had emptied, then banged his own head against the wall for a full minute.

Potter. Insolent, indolent, incompetent, insufferable. And a constant reminder of Snape's dismal youth, of his most enthusiastic tormentor.

And of the one person Snape thought he might have -

No.

Those damnable flask-bottom glasses were part of the problem. They made Potter's eyes seem huge, pools of bright molten green.

That, and the boy growing up strong and slender.

It didn't take long. Snape had been obsessed for years with everything else about Potter; what was one more burning lump in his stomach?

How to do it, how to do it? What was more important, the claiming, the humiliation, the secretive nature of the whole thing? There were so many factors to consider, each with its own nuanced flavor.

The easiest was most likely straightforward discipline of an unruly student. Make the boy grasp the desk and bend over to be whipped. Down with the pants, up with the robes, bring the birch rod down across that fine pale arse of his a dozen or more times before cupping Potter in his hand, stifle the cries of outrage with the threat of house points and detention - the boy was stupid enough to let those actually matter, even when being violated - or even just the insinuation that Potter couldn't take it... and then slowly and deliberately stroke him to orgasm while taking his arse. The confusion and distress over his own pleasure would make Potter a ready plaything, to someone with the wit to manipulate him.

Hell, he could end up with the boy whimpering Severus's name as he was tied to a bed with silk scarves...

No. Too much bloody work. Playing to one's strengths was always best.

And so, a few days later, Snape carefully did not watch as Potter drank his pumpkin juice at dinner. By the end of the meal the boy was yawning ever so slightly; by the time he'd got to the hall that led to the Gryffindor common room - alone; Weasley had a well-deserved detention, Granger was no doubt in the library - he was staggering, leaning against the wall to stay upright. No one else was in the hall when Snape came up from behind, took Potter's arm, and activated a portkey to his private quarters.

From there it was simplicity itself. Potter was slightly weakened and suggestible, with just a lace of aphrodisiac... something to make him languid, as Snape stripped him and spread him face-down on the bed. When Severus's slender fingers began working oil into Potter's arse, the boy began to whine, the bedclothes muffling protests punctuated by no and please. He began to cry when Snape penetrated him, but a few minutes of very precise fondling and the boy was pushing his arse back against Severus's hips. He only made a small "-ah-" sound in the back of his throat when Snape came, and a similar small noise when he came himself a few moments later.

Sweating, as close as he'd been in years to gasping, Snape left Potter sprawled there, and went to wash himself. When he returned, Potter was on the floor, on his hands and knees, and Snape readied a Stupefy, thinking the boy had recovered somehow and was trying to escape.

But Harry did not move.

Severus did.

It took forever to cross the room. But finally he stood before him, ruffling his hand slightly through Potter's hair. Harry looked up at him.

My god, those eyes.

Snape's fist tightened in Harry's hair, and the boy's lovely, slack mouth fell open to accept Snape's reborn erection. He knelt there, softly mouthing Snape while his gaze, Lily's smouldering gaze, never wavered.

By the end of the evening, Harry was trying to kiss him. Snape did not Obliviate him; instead he gave him a potion of repression, which would block the memories until a spell was cast to release them. And only Snape knew the spell.

This went on for several months.

An opportunity would present itself, on average, about once every five weeks. In public, in daylight, Potter was the same hateful, arrogant, expectant-of-all-glory-and-praise-becaus

e-I'm-the-hero brat.

In Snape's bedchamber, he was a pliant, delectable toy, readily broken and quietly eager to please.

Harry was like that the night that Severus took him to Voldemort.

The Dark Lord studied Harry, kneeling passively before him, awaiting instruction. "What have you done to him?"

"Made him a plaything, my Lord." Snape's voice was as flat as ever. "Eroded his will and taught him to please."

A flicker of amusement crossed Voldemort's face. "I'd not thought you in the market for a catamite, Severus."

"I admit the boy finally did have his uses after all. And now I give him to you. You may still kill him with ease, my Lord - but you might also use him as a symbol of your power."

The corner of Voldemort's mouth twitched. "The Boy Who Lived To Crawl At My Feet. It has merit, Severus. My only regret at the thought is that old fool Dumbledore is already deceased. This would surely kill him."

"Indeed, my Lord."

Voldemort turned again to Harry, and cupped the boy's face in his hand, stroking his thumb almost tenderly over the cheekbone. "So much between us, Harry. For it to end like this... is almost sad. But fitting, somehow. You never had the slightest chance."

Taking a small step backward, Snape cast the spell.

Harry stiffened. Awareness flashed through his eyes. Memory.

Outrage.

And then Snape was in his mind.

I did it, Potter. I did all of it. I broke you, and made you want it. Made you want me.

And I did it for him.

With an incoherent bellow, Harry shot to his feet, his power surging as it never had. He unleashed a torrent of blinding energy at Voldemort, who stumbled back under a hastily erected shield spell and realized to his horror that the only reason he had survived the initial onslaught was that Harry's attention was split between him and Snape.

"You used me!" Potter screamed, the magic streaming off him. "You violated me!"

"I freed you!" shouted Snape, his skin already bubbling. "To do what must be done!"

For one terrible instant, Harry locked eyes with him, and then he jerked around towards Voldemort, who whimpered in the back of his throat as he saw his death at last. Harry's power flensed him, shredded him, annihilated him.

When the light faded, nothing remained but a stain.

Severus folded to the floor. Harry crossed to him, cradled his head and shoulders in his arms. "Professor."

"No... use... being polite... now, Potter," Snape murmured. His face was ruined.

"You had to pick the most hateful way to do that, didn't you."

"You wouldn't... recognize me... otherwise." Harry started to try and lift him, but Snape grabbed his arm, and Harry waited. "Potter... I am... sorry. For that... for everything."

Harry clenched his teeth. "There is no way in hell that can possibly make it better."

"I know. Had... to say it. You did win."

At that, Harry seemed to deflate a little. "I need to get you to Madam Pomfrey."

"Too late. Too late. Potter... the spell... the memory spell... Alchemae Incognitus. You can lose... just those memories. If you want."

"If I want? Why the hell wouldn't I -"

And then he stopped. Looking at something far away.

Snape managed a very small smile. "That... that's up to you. Farewell... Harry."

Severus's head fell back with a last exhalation.

That was how Ron and Hermione found them.