This song expresses the relationship between model Yu-chami and her younger sister Yui-chami.
The lyrics are from the younger sister's perspective, and are based on the sisters' mysterious rule that if they like the same things, the older sister takes priority.

As the second son myself, I can't help but empathize with the "view from below," but the song is secretly grateful for the sense of security that comes from knowing that the older sister takes priority, even though she always takes the lead. It's a bit embarrassing, but...