That part just shows that what happened between them was tails. Meaning.....!!!
I also like Muryu's way of differentiating tails, there's always those white featherlike thingies when the scene is in tail, especially important ones.
this is why I think Juda gained awareness when Dohwa was supposedly gonna confesd to her again. If he did at that time, would it have made s difference somehow? I just hope to see Juda and Dohwa in the new webtoon, where she's the one making him remember.
I also like the color of the "badump" effects, it's blue and pink, showing they feel the same way at that moment. Muryu is a genius.