Look. Nobody could deny that, as a kid, Dick was a bit of a handful. Not just as Robin (though Bruce could certainly attest to those shenanigans), but just... y'know, around the Manor. Oh, could Alfred tell you stories. Swinging off chandeliers, sliding down bannisters, there was the table-surfing incident, and the time with the skateboard and the grand staircase... he was rambunctious, okay? Precocious, even. Adorable, surely. But also, probably nearly gave everyone a heart attack a time or three.
Good times. Fond memories. Kinda hilarious in hindsight, right? He can laugh at himself. Which maybe makes this whole thing... sillier, because holy crap is this probably some kind of karma. Right? It has to be. Has to.
Agreeing to babysit his newest little sibling had been an easy 'yes'. Obviously! A chance to get to know them, and also, like... not something he's unaccustomed to. Big Bro duties, y'know? He likes hanging out with the younger ones, showin' 'em the ropes, being the fun big brother. And he'll be honest, when Bruce warned him that the new addition to the family was, well... 'a bit of a handful' themselves, he'd sorta... waved it off.
He's Nightwing, for crying out loud. The first Robin. He can handle a handful. Nobody's gonna out-handful him. Right?
...Well. Dick's getting a run for his money today, apparently. And, yeah, he's really just got to assume this is karmic justice. This kid is running him ragged - but hey, he's kind of having a ball? That's just how it goes.
"Okay how did you even get up there?" He is genuinely not sure if he's exasperated, or impressed. Maybe both? Let's try 'both'. "Come on, back down before you break something! Object, bone, or otherwise."