A/N: This is a short piece that was written for an RP I was in. So if, on the off-chance, you've seen it floating around on Tumblr under either along-came-a-snape or have-a-snack, just know that both of those accounts are mine. And both are very inactive now. (The first, because the RP group was disbanded and the second, because I'm just plain lazy.)

The prompt for this was 'Old: I'll write our characters growing old together'. This was prompted by Anonymous on my Severus Snape account mentioned above.

I do not own Harry Potter and am making no profit what-so-ever off of this very short story.

Warnings: Besides Snape being a really cranky old man? The closest thing to a warning is the questionable 'why are Severus and Sirius rooming together?' thing. This story is NOT slash but if you want to interpret it that way, you might be able to make something of it if you squint really hard.

AU (obviously, since Severus and Sirius are alive) and post-New Generation. As in, it takes place after James, Albus, Lily, Scorpius, and all of them have gone to Hogwarts and graduated.

I think I covered everything... Enjoy!

They'd been walking for fifteen minutes now.

Never in all of Severus's life had he felt his knees ache as they did now, nor as irritable about walking around Muggle London. Except maybe six days ago when his ever persistent roommate had convinced him to run to the market with him for milk.

The year was 2034. The children were louder than he remembered them being thirty years before. There were more widgets that he didn't understand from when he and Lily had been children in a Muggle neighborhood. The televisions were larger, brighter, and multi-dimensional. Music had evolved beyond belief from phonographs, playing louder sometimes than an actual on stage performance. He didn't understand half of the songs he heard, either, nor did he want to. And the cars looked outrageously ridiculous.

There were reasons he didn't like to venture out and away from the two-bedroom flat he shared with a certain imbecile. It was simpler inside, after all. Plain, with an old flat-screen television that was approximately thirty-five years old now. They didn't use it at all. Well, he didn't use it at all. He couldn't say as much for his roommate, but given how often the other man tended to step outside to socialize, the television didn't exactly get much action with him, either. He suspected their use of magic also helped sustain it.

Not only was their television old fashioned, but so was the magic they kept to, Severus's Potion books (when he felt the need to refer back to them) were rather outdated as was some of the ingredients that had been substituted years later for others. A lot could change in thirty years, after all. A lot had changed since he was a child, too.

It was simple inside their flat. Well, simple living, that was. If one could call it that. Ah, no. Rephrase. The building and its amenities were simple. Nothing about their actual living situation was simple, was it?

Severus glanced sideways at Sirius Black, still adorning proud shoulder length hair, albeit silver. A nice silver, at that. Like the sheen of silverware, except perhaps not so bright. Severus's was a dingy peppery mix of gray and black, though he didn't care much for it. It looked about as spectacular as it had when he was eleven. That was of no concern of his.

"They've changed this station dramatically." Severus complained as he glanced about, briefly coming out of his thoughts. He soundly ignored the Muggles milling about with their suitcases and rushed pardons. Merlin, had the station changed though. It was perhaps as dirty as he remembered and that appeared to be the only similarity from his memory of when he was seventeen. Now, the station was also adorned with electronic advertisements projecting from the walls and the trains spiffier than he remembered them. He'd not been here for nearly sixty years, after all. The changes… it was another reason he made such valiant efforts to never leave his flat.

"I guess so, yeah." Sirius shrugged a shoulder, glancing about as if just noticing all the gaudy additions. "Not much different from how it was last time I was here. Just a bit more colorful." Ah, right. Because Sirius had accompanied Harry when his kids were off to school. He suspected twenty years wasn't as big a deal as sixty. Severus scowled as they continued their amble, finally reaching platforms 9 and 10. "C'ept this. This is exactly how I always remembered it." Sirius stepped forward with a grin, watching a Wizard dressed in out of place Muggle clothes pass through between the platforms unassumingly. "You know they tried to tear it down to rebuild it several years ago? 'Course, it didn't work. Serves 'em right it didn't, too, what with the gateway and all." He exclaimed cheerfully. Severus had to resist pinching the bridge of his nose at the man's excitable tone. The old git was practically bouncing on the balls of his feet now that they'd finally reached their destination. Some things never changed, really. Sirius Black was one of them.

He allowed a sneer to creep up on his face as Sirius's statement, brushing past him as he made his way toward the solid wall. "Ah, yes. I'm sure that baffled the Muggles to no end." He replied with his typical drawl, passing through the wall suddenly, only to emerge on the other side where the Hogwarts Express was already stationed and depositing children.

"Late, we are! They've already arrived! Told you we should've left earlier!" Sirius came ambling out in front of him yet again, eagerly loping his way toward the station.

"And I told you that I wanted nothing to do with this nonsense. You can pick up a sodding child on your own, can you not?" Severus wasn't even going to attempt to keep up. Actually, it would be much better if Sirius just took off ahead of him. The less he had to deal with, the better.

As it was, Sirius had other ideas. Well ahead of him now, he'd turned himself around so he was walking backwards, not exactly mindful of bumping into the Witches and Wizards and their young ones around him. Severus let out a disparaging sigh as Sirius called back out at him. "Well of course I can, but you, foolish Severus, have not stepped foot outside your room in four days! Can't be having you rot away and greasing up every corner of it, can we? If you kept at it, you'd pass on forgetting what the sun looked like." He chortled amiably, stopping momentarily to allow Severus to slowly catch up yet again.

"I would prefer it that way, yes." Severus rolled his eyes. "And the only reason I've not stepped foot outside my room, as you so quaintly put it, is because I'm still struggling to overcome the fact that you nearly burned our flat down." He snapped, still clearly irritated over the incident. "Honestly, how does one catch an entire stove on fire? You've still yet to explain that one properly. Just what were you doing?" It was a conversation they'd had several times over the past four days and Sirius still had yet to give a proper answer.

As Severus finally reached where Sirius patiently stood waiting, the man turned around again, a sheepish look on his face. "Still not over that, eh? Poor frightened Severus can't handle a little heat."

"Hardly. But if I'm to die in that flat, it most certainly will not be because of your abundant idiocy."

"Hardly, yourself. That fire was caused by a stroke of brilliance—Tut, no, I won't say." Sirius cut Severus off with a knowing grin, just as he'd opened his mouth. "I put it out, didn't I?"

Severus was glancing about now for the familiar unruly mop that would be Potter's grandson, considering that Sirius appeared to be too distracted with their conversation. Grandson of the Potter of the Harry variety, that was. Merlin, he knew too many of them now. It was quite appalling, actually. "Did you?" He retorted, sneering suddenly and blatantly at Sirius. "If memory serves me properly, your aim was quite off. I do believe I was the one that extinguished the flames."

"Nah, I definitely hit you in the face with that Aguamenti on purpose. Was a brilliant shot after all, wasn't it? Don't you think? I'm not that senile yet, you know. Oi— REED!" Sirius was suddenly flailing his arms high above his head to catch the boy's attention. As Reed Charlus Potter made his way over to the two, a ridiculously elated smile crossed his face at the sight of his great great Godfather flailing his arms about dramatically.

Severus watched the two embrace before Reed, James Potter II's only child began prattling about his second year at Hogwarts. Black eyes vaguely caught brown ones and the two simultaneously scowled at one another.

"Hullo, Professor Snape." The boy solemnly greeted him, as if Sirius's hand on his shoulder compelled him to force such niceties on the bitter old man before him. Severus supposed it was in the majority of the Potter genes to hold an inexplicable dislike of the greasy haired man. It probably didn't help that of all four Potter's he'd taught, Harry and James had been among his least favorite.

"Mr. Potter." He returned dryly, impatiently, again marveling the fact that the Potter name had survived into his old age. Lily's great grandchildren, Severus thought with a dull brief ache. He quickly pushed the thought aside.

"Don't look so sour now, the both of you. Got a fun week ahead of us, we do!" Sirius clapped both the child and Severus on the back eagerly as they made their way back toward the Muggle station.

"I don't see why I have to stay in your flat with…" Reed trailed off, brown eyes regarding Severus briefly before glaring at the ground. "Mum and Dad said you could stay in our house, after all." He directed toward Sirius.

"And leave old Snivellus by himself to soak up the isolation? Never!"

The former Slytherin felt a heavy breath expel from his nose with disapproval. Right, let's repeat old bothersome nicknames for the younger Potter generation to hear and toss about. It had Reed smiling again, however, which was what Severus expected Sirius was going for.

"Need I remind you that I'm not the one that volunteered my personal retired time to spend with a child after I've exhausted nearly forty years of it doing so?" He grumpily retorted. It was rather inconvenient that James and his wife had business out overseas and were unable to retrieve their only son for the first week of Summer. Naturally, Sirius had eagerly stuck his nose into the situation, asking what they'd intended to do about a sitter. James hadn't exactly been keen on the idea of Reed staying with both Sirius and Severus, but in the end had relented to his great Godfather's almost puppyish pleas. "…And need I also remind you that I am not above poisoning you?" He threatened after Sirius had studiously ignored him.

"Ah, shove it already Severus. Like you could remember how to mix a Potion anyway. You'd scratch your arse and forget what you were doing, you would." The former Gryffindor grinned at his own joke.

"I'm also not above throttling you out here in the middle of London."

"Yeah yeah, heard it all. Every single day for the past five or so years we've been living together. Suppose being threatened by you every day beats senior living though. You're too soft to do it anyway and we both know it."

"You'll think I'm brilliantly soft when I'm smothering you in your—."

"Tut! You used that one yesterday too. Did you forget? The grease has finally seeped into your brain."

"Sirius—"

"Ah! Here we go." Sirius halted suddenly in front of a restaurant he'd spotted earlier. "I bet you're famished Reed, yeah?" And without another word or seeking Severus's approval, tugged the younger boy along behind him into the hole-in-the-wall dine-in.

Severus sighed heavily, wondering why he allowed himself to be subjected to such shenanigans. And thus the rest of his afternoon went as such as he plowed into the restaurant behind Sirius, wondering not for the first time how his life had ended up as such.

Ah, irony always had the last laugh, indeed.

A/N: So, I felt like this could've used a lot of explanation. The how and why and build-up behind the two living together in the first place. But given that this was a prompt on my RP account, I wanted to keep it simple and hold the interest of those who didn't really care for the idea of an amiable Severus/Sirius thing. I've thought about expanding on it before, but it's such an enjoyable piece (to me) that I don't want to distort the feeling behind it by dragging it out more than I thought necessary.

Anyway. Constructive criticism and reviews are all more than welcome!