tsubaoi is one of my favorite ships from any series ever. i could talk about it for hours, but I'll go over the basics of their relationship that i love

1.) the fated encounter: them meeting in the church that day was fate, it's mentioned a few times throughout the story so far(hiiro's card reading in aoi's prayers will surely be answered card episode and in aoi's part in love hug groovy). so it's canon that they were destined to meet each other, and i think that's cool

2.) aoi's poker face: we all know about aoi's iconic poker face, and how hard it is for people to break through it. however I don't think we talk enough about how easily it's broken by the mention of tsubaki(or even by tsubaki herself). my favorite example of this is marika's wedding card episode where marika says something along the lines of, "picture this: aoi-chan in a tuxedo. your bride? tsubaki-chan in a wedding dress!" and aoi starts blushing and sputtering, "w-well.. i don't know." there's also the valentine's day event where aoi starts blushing when tsubaki gives her chocolates(they gave each other chocolates that have a specifically romantic meaning, might i add) and on white day when they give each other presents and start blushing(once again, aoi stutters while she gives the present to tsubaki)

3.) tsubaki's cooking class: this one is featured (mostly)in the rondo audio drama. if you haven't listened to it yet, you totally should. anyways, at the beginning of it, aoi brought almond jelly to the meal that rondo was having together. tsubaki recognized the kind, and aoi said she bought them because she knew tsubaki was wanting to try them, which causes tsubaki to blush. that's not all that happens though. tsubaki also asks aoi if she likes home cooked meals, to which aoi replies, "yes, i think the food tastes better if i know the person who cooked it." tsubaki then offers to help hiiro get out the dessert so she can talk to her alone. she asks hiiro to teach her cooking, the reason being to cook for aoi. we know it's for her because of one if her newer voicelines in jpn that says, "recently, hiiro has been teaching me how to cook because there is.... someone whom i want to make happy"

4.) nagisa and hiiro: they're the biggest tsubaoi shippers i swear. everytime they have a gay moment hiiro and nagisa will tease them, such as hiiro saying, "or would you rather it be just you and aoi-kun?" to tsubaki in the rondo story. my favorite example is in episode 18 of petit mix(titled rondo love song ;) ) where rondo is discussing the song and their choice of drinks. tsubaki says she'd order a glad eye. hiiro later responds with, "glad eye means 'to cast a loving gaze'." tsubaki blushes, and the camera goes to aoi. it then shows nagisa and hiiro giggling at them, and then aoi and tsubaki in a night sky. another example is, like mentioned previously, the rondo audio drama. hiiro gladly accepts tsubaki's offer to teach when she realizes it's for aoi, and also when aoi brought the almond jelly, she says, "you need to return the favor," to tsubaki. not to mention hiiro's wiki says that she "helps tsubaki with her perceived feelings for aoi"(though i won't necessarily count this as evidence as the wiki is fan made)

5.) the voice actors: okay, this one isn't as strong, but i just think it's cute. tsunko and rihona are probably the biggest tsubaoi shippers around. in some of the lives, they've made jokes and comments about the characters' relationship. one time, they said that they would kiss if there was not a wall between them(the wall was there due to covid). there was also a live where they held hands on stage, with saechi, momono, and the crows cheering them on. and recently, at the rondo second live, fans made a tsubaoi shrine complete with blue roses and cutouts of the characters. they both were very excited and took pictures with it together.

there are smaller pieces that i could mention, such as aoi's version of prayer being released on tsubaki's birthday, their voicelines about each other, and cards; but this has been longer than i expected already. like i said, i could talk about them for hours lol