I love Aoi and Master's older brother. His brother especially seems happy to let them do what they want, as long as it's safe and doesn't get in the way of their other obligations, which is probably what the adult should do, give them a safe place for this to happen, since it's going to happen anyways (if we want to step into the realm of realism for a bit).
Aoi seems worried about Master and Sasha's relationship being too weird or her scaring master way/breaking him, since she lets up after Sasha says "I did think about my actions, and i kept on wanting to talk to Master". Sasha isn't a liar, so she believes her, even if she still calls them 'idiots'
Sasha wanting to read his ero-manga with Aoi is also kind of sweet, obviously that may not be her thing, but Sasha really seems to share and want to share Master's passion for it, and maybe justify it (see, i helped make that!), but it seems more emotionally grounded than just selfish, if that makes any sense. It solidifies her seriousness for Master, even though they're not truly together yet, since she's so openly blasé about everyone else so far, and Aoi probably knows how blasé she is about everyone else, since Aoi spoke to Master about Senpai (chapter 36, talking about chapter 30.5 senpai)
I could be reading into it too much, but i really like her two school friends, they're a good normal recalibration after the crazy drop in the previous chapter and the general hijinks of the whole threesome arc.