I don't actually have one set headcanon! Episode 19 has so many open-ended parts to whatever you want to focus on that it can make for an easy creative exercise specific to the Azu fandom! I've explored it as a chapter in Flutter, I've dived into the subject for a comic once...and most, if not all, of us have accepted Episode 19's "Tomo comes into Yomi's room via her window" tidbit as canon for both iterations by now.