Constellation Fever (星座フィーバー) is an appeal-like feature seen in the Constellation System. The performers use this as they enter the stage.
Theory and Description
Earlier in the series, Constellation Fevers could only be executed after the respective performer has gained the Proof of Constellation for the necessary constellation. For an example, Ran, Ichigo and Seira are allowed to perform a fever as they've acquired their respective constellation from their previous performances.
As the series goes on, a Proof of Constellation is no longer needed to perform a Constellation Fever.