By Her Holiness Hayase Nagatoro's will, they've entered the flirt-teasing-backfire phase of their relationship…
I'm impressed that Gojo learned to make an overbust corset for Marin's costume, and has upgraded his skills from straight cloth Japanese clothes to goth lolita and now actual tailoring. He's really thorough in upgrading his trade craft. There's professional youtube seamstresses who fuck up making corsets the first time.
I also like the experienced cosplayer (tape, makeup shades) vs zero hesitation dedication cosplayer (reminder that she shaved her eyebrows off totally) dynamic between Marin and Juju. It's like they're trading skill tips and secrets with each other, and while Marin is obviously the less experienced, they both sort of make the other jealous in a healthy way.
Shinju and Wakana really are alike in so many ways. It's endearing how perfectly they get along.