插一杠子

Traditional (Taiwan): 插一槓子

chāyīgàngzi ㄔㄚ ㄧ ㄍㄤˋ ˙ㄗ

    • to step in midway and meddle in something others are handling

Character by character

Saying俗语俗語

Idiom惯用语 · In everyday use

Literally
stick in one pole
Meaning
To step in midway and meddle in something that others are handling. It is mildly critical.

Sources