Chen configured the shape of her tails as a light bulb. Moyazou was understandably insecure about the result that a little speech bubble WITH a light bulb is placed above it.
SFX translated. They're pretty important to the joke, yet they're almost untranslatable... they're supposed to communicate that Ran was getting pretty antsy and restless with her tails as she carefully and meticulously prepared Yukari's breakfast, and then gets really excited when Yukari comes down the stairs. It's tough to get an emotion across in a sound effect in English.
Also, do we need an "expressive tail" tag? We don't, because we already have one. Would you look at that.
