Yes, he had better hold his tongue as to how and why she died.
She clearly had more to say, but held her tongue.
Sometimes he just didn't know when to hold his tongue.
So she held her tongue and let him make his point.
She already knew the answer, but couldn't hold her tongue.
Or what more than to hold your tongue about it?
It's a good country if you can learn to hold your tongue.
I'm not a man to be holding my tongue when I've been thinking.
He held his tongue as she rose from the table.
We won the point but lost the case, so after that I held my tongue.
Idiome