"I - wait what? How does that work? Fish and people have babies in totally different ways and - and breathe in different ways - how can you have something that had babies and then some of them ended up changing over time into fish and some of them turned into people????" 

"If you have a bunch of small changes they become really big changes. It's not a big change to evolve lungs that can breathe air a little bit, and then they get a little better, and then a little better, and there's lots of food and no predators on land at that point so it makes sense for some animals to evolve to be on land, and then their fins slowly change to be better at walking on land, and after millions of years you get people."

(They arrive at the reading room.)

"So...the ancestor of fish and people started out more like a fish? What was before that?" 

"The very first life was one-celled organisms-- a cell is one of the smallest units that make up your body, I can draw a picture of one if you want-- and then after that was algae I think?"

Masozi doesn't know the word 'algae' and looks blank. 

"Uh, the green stuff on top of lakes?"

"Oh, that? ...Do you mean the kind that has long stems and floaty leaves, or the kind that's like grass with bubbles, or the kind that's sort of like threads tangled together, or the kind that's gooey like mud?" 

"Threads tangled together, I think. --Anyway, evolution is why everyone finds sex so interesting, people who wanted to do the thing that makes babies a lot ended up making more babies."

"....Right. I guess that makes sense. But - why kissing, then? That's not related to making babies, and lots of times people kiss and then don't fuck so it's not part of sex, it's just...a different thing that people find interesting for some reason?" 

"Mouths have a lot of nerves and people tend to like touching parts of their bodies that have a lot of nerves to other people's bodies, especially if they're attracted to them. I'm not sure why that evolved? Maybe as a way to make relationships stronger since human babies take a lot of care so you have to make sure people like each other if they're going to have one, so evolution was like 'here's a sex-associated thing that is also fun and makes you like people.'"

Shanghai seniors are not sure why Masozi's sex ed is happening in the reading room but FINE they can tune them out while they concentrate on their homework.

"Huh, I guess that makes sense. Why do people like cuddling even when it's just with their friends and they're definitely not going to have babies?" Because, for example, they are ALL BOYS. 

"Well, if you have a thing to do to make people like each other you might as well reuse it, right? People cuddle kids, people cuddle their friends, people cuddle people they're fucking..."

"...Do people cuddle kids?" Masozi's childhood did not exactly contain a lot of cuddling, not once his older sister died. He...supposes he vaguely remembers his mother carrying the babies around, but usually that was just because they couldn't walk yet or weren't weaned yet? And he can't actually remember being that small. "I guess. So - it's a thing to want to cuddle your friends because you like them, but not to want to kiss them?" 

"Yeah, people do that all the time. I like cuddling everyone but I only want to kiss some people."

Masozi nods, seriously. Then frowns. "What if...you want to play with someone's hair and hold hands with them? Is that a thing that's more like cuddling or more like kissing?" 

"Zaizaiiiiiiii do you have a crush?!"

"- I don't know! Nie Huaisang told me a list of feelings people have when they have a crush? And I - think I maybe have some of them but not all of them? So I don't know if it's more just - liking someone a lot because they're your friend and a very good person?" 

"If you want to hold someone's hand because handholding is generally nice, it's not a crush. If you keep thinking about how nice it would be to hold their hand and it pops into your head at totally unrelated times, it's a crush."

"Oh."

Masozi considers this intently. 

"I...don't think I start thinking about it at random times? Just if I - see them, or remember something they told me, or think of something I want to tell them about." Also he's catching himself being weirdly shy and circumspect in talking about this? He isn't sure why, it's not like he would have thought it was embarrassing to ask the question, and yet.

"...Okay so Nie Huaisang told me that romantic feelings are - 'when you can't stop thinking about someone and you feel warm and happy when you think about them, and you want to hold hands with them and hug them and kiss them and give them presents and spend time together just the two of you, and it's really important that they think well of you.' I - wouldn't say I can't stop thinking about them, that would be stupid when I've got other things to do, but I guess I - end up thinking about them a lot while I'm doing things. I...dunno if I want to kiss them, I think I don't understand kissing enough yet to really imagine it properly and so it just sounds stressful? And I don't have anything I could give as a present, unless - doing a really good job on learning Mandarin because it makes them happy is that sort of thing? And I have lots of reasons why it's important for them to think well of me, I think, so I would no matter what." 

"If you're doing a thing where you're like 'hypothetically, if these were my feelings about you, would this be a crush' then yes I will go out with you."

Oh no is it going to hurt Wei Wuxian’s feelings that it’s someone else? Masozi did not predict this as one of the possible outcomes at ALL.

“…S’not you. Sorry. I - it’s someone from Shanghai enclave but it…might be bad for me to go out with them? So I haven’t. Said anything.” 

"Oh, it's a girl."

"Nnnnnooo...." Okay, maybe it's actually more uncomfortable letting Wei Wuxian speculate like this rather than just telling him. He ducks his head and lowers his voice to a whisper. "It's Lan Xichen. But it - seems maybe bad? Also he has a boyfriend already, right?" 

"Why would having one boyfriend mean you couldn't have another boyfriend? It's not like it's girls."