It’s an odd phrase, sounds like something translated from another language into English. ‘Before his mother’s tongue gives me grief’ isn’t an idiom I’ve ever come across in English. Without context it just sounds like what it says, i.e the person speaking is asking someone to put someone else in ‘the water’ before his mother starts complaining or making a fuss - giving the speaker grief. Maybe the scene is the baptism of a child?

It's obviously an idom. It's not an English one. According to multiple sites it means Поставь его в воду, пока его мать не начала причитать. . Which, I presume is a Russian idiom. I guess it means, do something, before his mother complains? So, given your native language, can you tell us what it means? I'm curious.

Perhaps there’s context missing (is this part of a longer text?) but by itself it makes no sense to me. It’s not an idiom used in English.