omg i'm gonna cry 😭😭 thinking about baiheng getting gifts for them when she travels and saving them for their birthdays but she can only keep them a secret for so long so she'll often end up telling at least one person, usually jingliu, what she got. she's so mindful of their interests and remembers if they've expressed wanting/looking into something specific. she's also familiar with their preferences for events so she plans the size, location, food, etc accordingly. i think she'd like to journal about their times together and how things went, whether it's a comment about how far yingxing has come since she's known him or something funny that happened. she puts a lot of thought into appreciating them and the time they have together and hopes she can bring them as much happiness as possible bc they mean so much to her and have brought her happiness too

for the sh i think it depends on the member. assuming silver wolf knows her birthday i imagine them celebrating hers by gifting her any games or merchandise she expressed interest in and maybe going to special gaming events (like we've seen in belobog and the luofu), spending time at arcades (i think i've posted about this before but the thought of them having a tradition of playing laser tag is so funny to me) or maybe they make plans to go to some kind of convention as her birthday gift (the thought of her cosplaying is so cute omg). i also think she has a list of places related to different media that she's interested in seeing (maybe museums for different technologies or games, places where things were filmed, or locations that are referenced in media she likes) so they might go to those as well. i think they'd get her a customized cake so it can be themed after anything she's currently into, go wherever she wants for dinner and spend the night playing whatever games she wants to. the thought of them playing anything competitive, but especially racing games, is so funny to me and i also love the idea of them playing games like overcooked that require teamwork but can get very frustrating 😭 very self indulgent hc that kafka prefers physical board or card games over anything virtual and asks to play those too (she also suggests it as a way to have blade more involved since controllers are difficult for him to use but she keeps that reasoning to herself)

i'm guessing firefly has some kind of record of her "birth" but idk if that's necessarily the day she celebrates. my incredibly self indulgent hc is that she chooses a day that has some kind of significance to her for her birthday instead (could be a pop culture reference or related to something that happened in her own life that she cherishes). she likes traveling and sightseeing so they make plans to visit different cities, famous landscapes or events (maybe festivals or concerts). they take lots of pictures and kafka gives firefly her credit card and tells her to buy whatever she wants but they also prepare their own gifts for her. silver wolf's are usually related to something they've discussed or done together while kafka's are often clothes and cosmetics. blade writes her a note reflecting on times and conversations they've shared and cooks something she loves for dinner in addition to getting her something she remembers her wanting (incredibly self indulgent hc no.3 that the two of them have matching bracelets bc firefly mentioned seeing friendship bracelets in a movie once and wishing she had someone to match with so blade surprised her). blade also spends time with her when she puts all of the pictures and mementos together in her scrapbook

kafka i'm kind of torn on bc i can see it going multiple ways. it's possible it's not something she celebrates bc she's spent so much time alone that it's not something she really cares for and it seems like an irrelevant detail of her past but i can also see her enjoying having a day to do whatever she wants to and i think she'd like gifts from the others. tbh i hc them as getting things for each other often so it's not like gifts are rare or reserved for certain times but i also think it'd be cute for them to have little gifts from their travels set aside to give her at once. i can see them having a movie night where she gets to choose what they watch and maybe they go out somewhere prestigious for lunch or dinner but i think at the very least blade makes a special breakfast for her bc i think cooking is one of the things blade enjoys doing for the others and kafka has always understood the significance behind the gesture and really appreciates it

i think initially blade finds the idea of celebrating anything about herself unnecessary if not ridiculous. i can see the conversation coming up when firefly celebrates her own and asks blade if she knows hers (she doesn't and i hc yingxing gave herself one bc she also couldn't remember hers). firefly suggests choosing a day to celebrate just like she did and explains that birthdays don't have to be a big deal and just having a day to appreciate her as her companions would be nice. blade ultimately acquiesces and when firefly asks if she has any specific day she cares about she thinks about her recruitment so that's what they go with. it's one of the few times kafka insists on cooking (but blade still ends up helping her). kafka gets her clothes and jewelry, firefly likes to gift her eye makeup and put together pictures that reflect the sh's times together (in some it's obvious blade wasn't aware they were taking pictures and they laugh about it) and silver wolf gets her silly things that she has no need for but holds onto regardless (maybe funny t-shirts, odd-looking plush keychains, basically anything that she thinks will get a smile and/or laugh out of her)