Loki is absolutely, positively, definitely not hoping Natasha will pay attention to his display of sorcery. Of course not. That would be silly, and pathetic, and also probably fruitless, because she has not so much as glanced in his direction for the entire thirty minutes they've spent together in the archives so far. She just stays at the table studying, her back to him, completely still and silent except for the occasional turn of a page. He flicks through a few more pages in the grimoire, tosses up another green flare of magic that is, perhaps, a touch larger and brighter than it needs to be. Perhaps more than a touch. Natasha still doesn't react, which at this point can only mean she's deliberately ignoring him and she wants him to know it. He's raised ignoring Thor to an art form, after all; he is quite familiar, from the other side, with the many shades of meaning involved. Natasha is nearly as fluent in that sort of subtlety as he is.
He looks speculatively at the page in front of him, then at Natasha. Well, he is supposed to be improving his skill with illusions. He leaves an illusory double with the book, cloaks himself as well as he can, and creeps toward Natasha. His cloaking abilities are not what they should be, but he knows how to be silent, especially on the room's thick carpeting. He's out of her line of sight, and she has no magical ability of her own to sense him. Certainly he ca get close enough to startle her with a tap to the shoulder, but if he is supposed to be practicing illusions, perhaps conjuring something atop her book…
"Don't even think about it," she says, and he freezes. Possibly not just metaphorically. Winter in Jotunheim sounds balmy compared to the chill in her voice, and despite himself, Loki can feel his reluctant admiration for her creeping further upward.
For a moment he considers trying something anyway, just to see what she will do, but self-preservation wins out over curiosity and he makes a strategic retreat to his book. Fond of chaos and mischief he might be, but he is not actually stupid.
I have so much affection for this dumb little game and everyone in it, it's ridiculous. Also I kind of ship everyone and I really really need fanart of all the students in one big cuddle pile. I started mildly shipping these versions of Loki and Natasha pretty quickly, and then it turned into actually genuinely shipping them and having headcanons and feelings, so...I will probably end up writing more, even though there are many, many other things I should be working on than expanding a dumb little ficlet. At this point I'm not sure if I'll add chapters to this or add new fics.
Also, I realized after writing this that when Loki's practicing sorcery in the quad, his looking over his shoulder is probably less "hey hey is anyone watching, I'm being cool, somebody watch me" and more "better make sure no one's looking while I do this thing I shouldn't be doing," but whatever, I think this still applies.