A/N: based on a Tumblr post and subsequent prompt! Title idea from riversgirl75! Let me know what you think :)
It starts a few weeks after September 1st, initially nothing strange enough to really draw his attention beyond answering the innocuous questions like 'do you have a favorite color' and 'are you allergic to any flowers or plant life.' Weird, but he brushes them off, assumes it's just an effort to get to help them get to know each other like normal people – people who finally don't have a homicidal maniac breathing down their proverbial (and occasionally literal) necks. So he asks them back, learning she hates salt on her eggs, loves swimming at dusk, and secretly read Ron's entire collection of Martin Miggs comics during his first year at Hogwarts.
But then it gets more specific, her questions. Ginny's latest letter had been filled with her usual humorous commentary on day-to-day life at Hogwarts – critiques on teaching methods (apparently Professor Sinistra's ban on caffeinated beverages in class was unacceptable), a run down on the week's Quidditch practices (along with gossip she'd gleaned about the other teams and updates on her negotiations with professional teams), as well as general boasting about how she's eating so much better than him (Harry felt silly having Kreacher cook for just one person). Then, reaching the bottom of the parchment and the dregs of his tea, Harry's eyes stutter over the postscript, 'what color is your cummerbund?'
Flicking his wand to send his mug to soak along with his other neglected dishware, Harry furrows his brow – unsure what exactly a cummerbund is and too afraid it's some mischievous flirtation on Ginny's part to ask Ron for help.
Considering who he's dating, he quickly tosses aside his second and third choices, and just as he's wondering where exactly he left Dudley's telephone number, Harry sighs and reaches for the floo pot perched on his mantle.
Before he can second-guess himself, he calls out for McGonagall's office and sticks his head into the now green flames, knees protesting at his position.
At first, he hears his former professor muttering darkly in her thick Scottish brogue before her sharply polished boots appear before him, peaking from beneath deep green robes. "You know I thought I'd have a break from Potter mischief until you and Miss Weasley had a child old enough for Hogwarts."
Harry fights the blush that threatens to rise at the mention of his and Ginny's hypothetical future children and clears his throat. "Funny you should mention Ginny."
Settling down on the plump tartan stool tucked close to the broad fireplace, McGonagall arches a dark brow questioningly. "Romantic troubles with the youngest Weasley? You seem quite desperate. Don't get too clingy Potter."
Nearly choking on his tongue at the thought that his former professor is giving him dating advice, Harry shakes his head, "I'm actually not sure if we're having troubles?"
Her lip twitches, nearly smirking as her normally stern eyes lighten in humor, "Well that's a problem in itself, isn't it?"
He makes to answer, at least his mouth gapes open apparently hoping the act will force some answer to slide across his tongue, but McGonagall apparently takes pity on him, brushing at her skirt as she stands. "I'll fetch Miss Weasley and give you two a moment alone."
Harry spends the next few minutes taking in the changes McGonagall has made to the office now that she's headmistress, customary tin of ginger newts perched on her meticulous desk, tartan chairs cloistered around the fireplace like two tufted sentinels.
The door squeaks open slowly, hushed voices in the stairwell tickle at his straining ears . He nearly forgets his nervousness at seeing Ginny and consequently discovering whether the weirdness is a symptom of some problem – like breaking up with me, the specky git.
But it would all be clear soon. He hoped. Too bad can't clear things up with a snog…at least then I'd know if she's willing –
Harry ruffles his hair nervously and nearly pitches forward into flames, hands gripping at ashy lip of his small fireplace desperately.
Ginny smirks at his near miss, dark school robes swirling around her legs as she drops into one of the aforementioned tufted chairs. "To what do I owe the surprise visit? My letter should've arrived –"
Crinkling his nose to inch his glasses back up, Harry stammers, "Er- Well it did and that's actually –"
Apparently, he doesn't speak loudly enough because she continues, "Want me to nick you some food from the kitchens? Can you pass food through this way?"
"No! Ginny," Harry nearly shouts, confusion leading to distress, which lead to uncontrolled vocal volume.
"What? My Harry? Turning down food?" Ginny asks, nonplussed as her brows shoot into her hairline.
Harry clears his throat, nerves once again rising as he fights the inclination to ruffle his hair again. It's a family curse. "I don't know what cummerbund is let alone what color mine is."
Endeared expression sliding across her face, Ginny slips to the plush crimson and gold carpet, "Well, the first question is do you have one – Hermione says you need one and it has to match me otherwise it won't work."
Too stressed to pick up on any signals Ginny's sent to the contrary, his panic ratcheting up along with the pitch of his voice, "I dunno, should I? Is it something everyone has? Match you?" He pauses, brow furrowed, "Is this a shagging thing? Are you breaking up with me?"
Ginny makes to reach for his cheek, pulling her hand back once she recalls he's in the fireplace, she settles for a comforting smile and a steady voice one would normally use with a skittish kitten, "Uh Harry dear, take a breath – I'm not breaking up with you."
He lets out a relieved sigh that brings warmth to Ginny's chest beyond the heat of the flames in front of her. After he's calmed, his brow furrows again, "Then what are you doing?"
She's fairly certain he's been pulled back from the brink at this point so allows herself to roll her eyes, "Trying to coordinate for the dinner the Department of Magical Games and Sports is hosting?"
This fails to bring the clarity she expected as his emerald eyes narrow, "And the cummerbund?"
"Because you're my date?" Ginny answers slowly.
Harry quirks a brow, chewing his lip thoughtfully, "You do realize I had no idea about any of this – and I still don't understand the cummerbund – until you just told me, right?"
Things are moving in the wrong direction, as neither participant in the conversation grasps what's going on. Ginny scratches her head. "I never – I didn't – really?"
Harry smirks while a familiar blush rises on Ginny's cheeks. "Guess I've let myself get taken for granted. You just know I'll come running, cummerbund and all."
"You bet I do," Ginny grumbles around a swiped ginger newt.
Fiddling with his cuticles, forced nonchalance on his face, Harry answers loftily, "I suppose I could check my social calendar."
Ginny leans forward, flipping her fiery tresses behind her shoulder, dark eyes glowing in the firelight.
"Much as I want to kiss you, this is going to end up with two mouthfuls of ashes," Harry sighs dejectedly.
She doesn't respond beyond a scrunched nose, settling back on her heels.
"So you'll actually write me about the dinner this time?"
Offering a sharp salute, Ginny replies, "Mentally drafting my letter as we speak."
"And I'll find out what a cummerbund is – gonna call Dudley," Harry responds, nodding sharply.
"You're hopeless Harry James."
Harry clutches at his chest dramatically, "Hopelessly besot-"
"Finish that sentence and I may sick up Potter," a new voice calls from behind him. Ginny grins, "Ron's over?"
After offering a choice gesture to his best mate, Harry turns back to the fireplace, "Quite the sleuth you are Miss Weasley."
She sighs, face flushing for a much more pleasurable reason – when her boyfriend isn't a day's train ride away, "Don't call me that, you know it does things to me."
A throat clears from behind her, "I'll be sure to think of an alternative way to address you then."
Twin blushes rise on Harry and Ginny's faces, both stammering out variations on goodbyes. Harry clears his throat, eyes not quite making contact with his former professor's gaze, "Er- thanks Professor."
Ron's face slips in along side Harry's, still crunching what appears to be an apple, "This is the best day of my life."