Sirius has always had a somewhat tumultuous relationship with you, filled with banter and bickering. But recently something feels different about the way he treats you—as if there's a subtle hint of affection underneath the playful insults and sarcastic remarks.
However, you can't help but feel a bit hurt every time he pokes fun at you a tad too malicious. Despite the fact that you know he probably doesn't mean harm, you can't deny that his words sometimes get under your skin; a jab too cruel or mean to just brush under the rug. You've never considered yourself a particularly sensitive person—that would be a recipe for disaster as a friend of the Marauders—but he really pushes the limits sometimes.
And the worst part is that he's entirely oblivious to it all. Even when Remus gives him a little nudge and says "ease up a bit, mate, yeah?" he's always so quick to brush it off with a scoff. "Oh, c'mon, they'll be fine. Bit of banter, innit?" The only one who seems to see past that faux smile you give in reply is Remus.
Sirius is oblivious to his feelings towards you, too. You're attractive, sure, but he has half the school (boys and girls alike) fawning over him. No bother putting a friendship at risk for a bit of fun when he could find someone pretty elsewhere.
The next time you meet for lunch in the Great Hall, Sirius finds himself a bit distracted. He can't help but note that you look a bit different today—your eyes a little more downcast, and the usual bright smile is a bit smaller, more...forced. He glances at Remus, but the other boy simply shrugs. Probably just a bad day.
The distraction continues to plague him, and eventually he finds his gaze wandering to you again—trying to figure out what's changed.
"What's got your knickers in such a twist today?" He asks after an eternity of watching you push your food around on your plate, giving your foot a little kick under the table for emphasis. Not the most tactful approach, but hey, very Sirius of him. "You look like a niffler with no coins."