Tricky
There's a trick to it. Pull it back, loop it around thumb and forefinger five-hundred-sixty degrees, loose, but not too loose, slide the pins in. She needs three exactly, each seven centimeters of cool undecorated metal hidden in the dark of her hair, keeping it in place. She can do it in less than ten seconds; while it may not be gorgeous like Rangiku's luxurious tresses, it suits; never a hair out of place, not even when she uses shunpo. She prefers not to let her hair down in any sense of the phrase. It's not that anyone would ever mistake Ise Nanao for a loose woman if she didn't put her hair up, well… one person might just say it to annoy her. Maybe two if they decided to get sloshed together. But it would be his fault. Not that that would change anything. Ise Nanao is an excellent shinigami, and excellent shinigami do not settle for less than they want. And if they do… they don't, there's no point in contemplating pointless things. If, perhaps, it looked like they settled for less than they wanted… they had a damn good reason.
There's a trick to pretending you don't have what you want. There's a trick to getting more of it, but Nanao either hasn't learned it, or doesn't want to just yet.
There's a trick to it, protecting darling Nanao-chan without her catching on. He has no doubt she would beat him to death with anything she could get her hands on if she ever thought he was being overly overprotective. But he can't help it, so he just has to be very cunning, something he doubts she'll ever call him. It's quite ingenious, actually; he was always confident, he always had a reason to be. After all, Nanao, for all her demands he work harder, makes no motion towards leaving him to drown in sake or bleed to death by papercuts.
By teasing her like a child, he doesn't need take his feelings for her as a woman so seriously. By taking off to go a round or fifteen with Jushiro, he leaves her stuck in the office for hours completing the paperwork with her usual attention to detail. Her devotion to her inkset means she is never asked to go on missions, to the living world or otherwise. She can't get hurt if she doesn't fight, he figures, and she can't accuse him of looking down on her when he is passed out on the floor with his hat over his face. She is his Nanao-chan, even if she fights the pet name tooth and nail; she never fails to answer to it.
You have to admit it's quite a feat to be able to proclaim your undying affection daily and receive the most wonderful bruises in return. It's an even more impressive trick to be content with that for a little while longer.