"Fangirling" is a term used to describe extreme excitement over a certain fandom. For example, if you were a Hunger Games fan, and a new trailer came out, you might start fangirling, or freaking out from extreme excitement. 

“犯花痴”用来形容对自己钟爱的“迷文化”的极度兴奋状态。比如，你是《饥饿游戏》的死忠粉，最新预告片出来后，你就要开始“犯花痴”了，或者会“亢奋到崩溃”。

Fangirling是动词，来源于fangirl。fangirl指的是a rabid breed of human female who is obesessed with either a fictional character or an actor.（对某个虚幻角色或演员明星无限痴迷的女生），相对应的男生就是fanboy。