noun
substitute teaching; teaching in place of the regular instructor
Used when someone teaches a lesson (often in traditional arts, martial arts, or private tutoring) on behalf of the usual teacher.
先生が病気なので、今日は代稽古をお願いします。
Since the teacher is ill, please do the substitute teaching today.
代稽古を頼まれたが、同じ流派の者でないと難しい。
I was asked to do substitute teaching, but it's difficult unless you belong to the same school.