青青子衿悠悠我心
[qīng qīng zi jīn yōu yōu wŏ xīn]
"Qing Qing Zijin Youyou Wo Xin" refers to someone whom the user yearns for or cherishes. "Zijin" (blue collar) often represents a student or lover; while the whole phrase conveys feelings of yearning and lingering affection for a person.