打call

Borrowed from Japanese idol-concert culture (コール / 'call'), where fans shout coordinated chants and wave glow sticks. Reached Chinese mainstream around 2017 via 偶像养成 (idol-training) reality shows. Now used loosely for 'rooting for' anything — a friend's startup, a movie, even a tweet.

Mixed-script form is the standard written form — call is pronounced as English 'call' (kɔ:l), not romanized to pinyin. 为...打call ('to call for...') is the standard frame.