Severus tightened his grip around his cock as his hand moved faster, his hips struggling to keep up with the rapid pace.
He hadn't planned on this, hadn't even wanted to do it. Hell, even as close to the edge as he was, he still didn't want to do it. But it was the only way. He hated himself for it. Sure, there were plenty of things on the increasingly lengthy list of things Severus Snape hated himself for, but this without a single doubt in his mind topped them all. Locking himself in the bathroom of his long-time — admittedly dead — rival's anciently decrepit old house and wanking off to the thought of the girl he loved more than anything, all because he couldn't stand to see her in a pair of shorts. Temperature be damned, Hermione had to know what awful things those bloody shorts were doing to him. What with her prancing around the whole bloody house in them, every man in the building stared, drooled, and flirted, irregardless of sexual identity or relationship status.
It was a new kind of torture— pure agony, absolute and unfiltered— for him to sit back and watch her tight little ass bob around the house and have to know that he couldn't touch it, or any other part of her for that matter, for another ten months. Ten long, horrific months until she could finally be his. Completely. And she would. And when that day comes, he knows that he'll think back on the agony she caused him with those microscopic shorts and fuck her just a little bit harder, push himself in just a little bit deeper, and slap her ass until it's red underneath him. The thought of any clothing touching her sensitive skin, let alone those thrice damned shorts, will be the furthest thing from her mind.
Feeling the sweat trickle down the back of his neck, Severus raised his head from its position braced against the cool tile wall and bit down into his forearm to muffle the groans of her name from his lips. The image of what she would be like under him flashed behind eyes clenched shut as he spilled himself, his cum practically florescent as it landed against his robes.
Severus tried to calm his thundering heart, fighting to hold off his post-orgasm haziness. He had already been in the bathroom, been away from the meeting, for far too long. He had to get back out there before suspicious minds started looking. He turned around and turned on the warm tap with his clean hand, washing his cum covered one off, before leaning into the sink, perched on his toes, letting the warm water run over his too sensitive cock, cleaning it by hand. Magic would've been faster, but it only served to make him feel worse after the act was done, wiping it away as if nothing had happened. He would clean up his own messes. Until he had Hermione to do it for him, anyway.
He tucked his cock back into his robes, magicking away the remaining cum from his robes, knowing that no amount of real running water would serve to clean it off until it was properly washed. He returned to the meeting, satisfied but by no means sated.
Severus took up his perch against the back wall of Grimmauld Place's kitchen in a shadowy corner and looked on as his little Gryffindor lioness continued antagonizing him, bent as she was over the table to show something to a Weasley. Severus couldn't help but observe the thin piece of string dividing her ass into two perfect halves, only noticeable to one looking for it. Of course she was wearing a thong, why should she make this any easier on him. He cursed under his breath as he felt his cock twitch. Ten long months of agony awaited him. The future had never looked so deliciously painful.