One Mysterious Idiom

I still remember this one mysterious idiom told by one of the teachers in my school.
I have one interpretation for it, but not sure if that's exactly its meaning.

He's a Chinese teacher, very nice, but strict, and when he talked, a lot of new things we'd learn. He was scolding some students, he talked and talked, and finally he said:

"Macam meletakkan telur goreng di mulut orang mati.."
(like putting an omelet on a dead's mouth)

Then he left, and the students were left confused.

My interpretation is that he was describing a person doing something useless. But...it could have a different meaningXD! Is it a Chinese idiom translated into Malay language perhaps?