What does it mean to take Lagerstroemia indica as an auxiliary stick?

Take Wei Zi, the aid stick, as an example, to show support for the Youth League.

Ziwei is a limited luminous stick prepared by fans of Times Youth League. It is a strip-shaped handheld lighting device used to cheer for idols. In concerts or other public performances, fans will hold Wei Zi support sticks and wave them with the rhythm of music to express their support and encouragement to idols.