"Oh, yeah, I keep losing my pens! Thanks!"

Hm.  Can she get away with just handing him the one she's using, actually, see if he'll accept one pen = one notebook?  She passes it over and watches out of the corner of her eye as she digs through her bag for the second one, either to use herself or add to the swap depending.

He seems perfectly content with this swap.

Jiang Cheng, however, is full of seething anger.

Aaa?  Why is Angry Boy glaring again?  It wasn't that lopsided a trade, really, and enclavers get first pick of the good stuff, he's clearly rich enough to... not care what he gets in return...

Or... if he gets something in return.  Which.  Come to think of it.  Is apparently how it works in the Scholomance when a boy is asking you out.

Aaaaaaa.

Who asks someone out on the first day!  After knowing each other like barely half an hour- okay, half an hour of cool math talk, but still.  And she's just crushingly rejected him by acting like it was a swap and he just forgot the other half- or plausibly deniably rejected him?  ...or not rejected him, because she offered an obviously lopsided swap in return?  Or plausibly deniably not rejected him?  Does she want to have not rejected him?  He's fun to talk about math with and cute enough she probably wouldn't mind trying out Kissing And Stuff if they were outside the Scholomance where the stakes are lower, but they aren't, and two days ago she would have said obviously you want to date an enclaver if you have the option, but now that the option may or may not be here it's incredibly clear that enclavers come not only with the best stuff but with inscrutable social politics in her fourth language she is way underprepared to handle, such as for instance that boy there trying to burn a hole in one or both of them with his eyes-

Someone with the training and social graces to handle dating an enclaver would at this point figure out the perfect way of phrasing something to defuse the situation without offending Angry Boy further, while also not closing off the possibility of dating or hurting Wei Wuxian's feelings by stringing him along, and express it without a moment's hesitation in flawless Mandarin.  Connie is not that person.  She manages "Excuse me, please-" after a false start and then words close themselves off from her completely.

Wei Wuxian totally misses that any of this is happening and asks her a question about mana fluid dynamics.

It's a fascinating question, she will realize later, but right now she's not up to so much as 'oh hey, I think those girls over there are organizing a bathroom run, catch you later.'  She shoves her textbook in her bag and bolts.

She does take the notebook with her.  It's a good notebook.

Did Wei Wuxian just ask a girl out? He can't have asked a girl out. You don't date girls before you graduate. 

But you couldn't just accidentally give someone a notebook and accept a pen in exchange. Even for Wei Wuxian that's absurd.

It is against the rules of the Lan family to swear so Lan Wangji doesn't think what the fuck.

"You can't just give people notebooks because you like them! Notebooks are a scarce resource!"

"Chill out, Jiang Cheng, it'll be fine. I can write on both sides of the paper."

"You are going to get us all killed."