The mermaids had a special dance that they reserved for certain occasions.
It was a dance that they would only show to a few people.
If possible, it was a dance that they would only show to a single person if they could.
But then again, it wasn't as if life would go the way that one wanted.
That was why it was possible that they would have to do this dance several times in their lives.
Simply put, this was a mating dance.
This was a dance that they only did if they were interested in the other side.
If the other side accepted, then they would join them in this dance and they would get together. If the other side wasn't interested, then they wouldn't dance along with them.
This was the mermaid's way of making a confession.
I had seen this in the game before, it was even a special CG event that was supposed to be seen when one raised their favourability with a mermaid to the max. Since it was so special, of course I recognized it with a single look.