In Japanese, we use the expression 黄色い声援, "(let out) a yellow cheer" to describe a collective ecstatic exclamation that extremely enthusiastic female fans utter at the sight of a famous actor or the performance of their favourite band.

This expression is confined to denoting females who, fangirling over their idol, burst out cheering and screaming wildly. Your guess is as good as mine, though, as to why we use the colour yellow.

An audience letting out a yellow cheer, 黄色い声援:

 https://youtu.be/jrFxZVViA_I?t=463

In Japanese, we use the expression 黄色い声援, "(let out) a yellow cheer" to describe a collective ecstatic exclamation that extremely enthusiastic female fans utter at the sight of a famous actor or the performance of their favourite band.

This expression is confined to denoting females who, fangirling over their idol, burst out cheering and screaming wildly. Your guess is as good as mine, though, as to why we use the colour yellow.

An audience letting out a yellow cheer, 黄色い声援:  羽生結弦　アスリートの魂 (YouTube).