The title is loosely translated from a Vietnamese idiom

Nước đổ lá môn

A popular variation of this idiom replaces “lá môn” with “lá khoai” even though there are different types of leaves with the “khoai” prefix such as “lá khoai lang” (potato leaves, “lá” means “leaf” in Vietnamese), “lá khoai mì” (Cassava leaves)…

Nước đổ lá khoai

Another variation replaces the taro leaf with a duck’s head

Nước đổ đầu vịt

Usage

This idiom has the same meaning as the English saying “like water off a duck’s back”.

It is often used to express criticism or warning that some advice or action has no effect