I really like this pairing because they have that gap in their dynamic in public vs in private. There's also the difference in status, which makes it really exciting.
^ Which is interesting cause as far as I'm aware the female vocaloid that is most commonly represented as lesbian in Luka. I actually haven't really heard many songs with Yukari that match this trend.
^^ I don't think it's new, I'm pretty sure I saw a few if these a couple months ago, it's just that we got two images of it in a row. Im also not sure of where it originated.