She's back down a few minutes later. "She doesn't wanna talk about it right now. But she says I can copy her math homework if I want, so at least she's not too mad at me. Wanna go to the World of Colorful Sand?"
"I wanna invent a spell to be a line of defense against any environmental hazards you weren't in a position to notice - but before I start trying stuff - is my mana at capacity?"
"Safety."
"Oh, cool," says Brilliance, as a faint mana-coloured shimmer settles onto Bella's skin.
"Something unusual about how that worked?" Bella asks, looking at the pretty shimmer. "Ooh, I'm shiny."
"In some complicated technical sense or what? Also, how much of my mana is this drawing?"
"...Some," he says. "More than flying. Want me to work it up into something I can maintain for you?"
"Yeah, that'd be swell - and weren't you going to figure out percentages?"
"It's harder than I thought," he says. "I don't see it as numbers, I just feel it. ...Could you pick me up? I feel weird just hanging here. And I can get a closer look at the spell if we're in contact."
She plucks staff-Brilliance out of the air and props him on her shoulder.
Then Bella's shimmer brightens, wavers, and settles back down.
"Okay," he says, "there. With me hooked in, it's draining slower than you replenish."
And they are standing on a vast flat expanse of glittering sand that reflects the very Earthlike setting sun in millions of colours.