"Nygma," Batman starts, through teeth so gritted it's a wonder that they don't snap off, "if I have to get you out of this sort of situation one more time-"
"You're going to spank me?" He asks cheerfully, pulls free from the big bad Bat's grip and strolls away across the rooftop, "cuff me? Tie me to a table and teach me not to be so bad? As enjoyable as all of those would be, Batman, I'm not quite sure they're your style."
"Batman," he purrs, and spins on his heel to find the man right in his face. He's less surprised than he should be, they've known each other for far too long, "fine, I apologize for the inconvenience and thank you for your assistance. Is that what you wanted?"
"What I want," Batman says very deliberately, glaring at him like that's ever made any difference, "is for you to stop."
"Not going to happen," he smiles, bounces a little on his heels. And maybe they really have known each other for too long, if he can easily read the twitch of annoyance behind Batman's usual stoic mask, "I've finally found something that's even more of a thrill than crime. Why would I ever give that up?"
"Because," Batman snaps, and somehow manages to step closer - until they're almost pressed together, chest to chest, "you're going to get yourself killed."
"Maybe, maybe not," he says cannily, smirks as that twitch of frustration crosses the man's face yet again, "honestly, Batman, you should be pleased. Haven't you always wanted your, what do they call them, rogues gallery to successfully reform? Haven't you always longed for all of us to join the side of the light, and support you in your push for justice?"
"...Hn," Batman allows, continues glaring no matter how cheerfully he beams, "I've never wanted you to get killed while doing it."
"That is hardly a certainty, and you can't exactly tell me to stop over a 'what if'," he chides gently, takes great pleasure in the way that Batman's nostrils flare at his daring, "besides, Batman, I didn't know you cared so much. Haven't I always been a thorn in your side?"
"A briar in your shoe? A cloud covering your sun? A gas leak in your very shiny Batmobile-?"
"Nygma," Batman repeats, exasperated, and places one heavy gauntlet over his mouth. And he should shove it away, and he should keep talking as cheerfully as he ever does, but the sudden weight of it and the sudden look on Batman's face kind of saps any urge, "you get yourself killed, and I'll never actually accept you. Think of that, the next time you flail stupidly into danger."
...And he wants to find a retort to that, he really does, but as Batman swings away he finds that he can only stare after him and hold back a disgustingly lovelorn sigh.