What is meant by the old expression "milk baby"? As in, she was just a milk baby...?

Question

I've read or heard this somewhere, and I can't find it anywhere on the web. I asked an elderly lady, and what she said made sense, but I couldn't confirm it... "They were just her milk babies..."

Answer 1

it is same thing as mommas boy

Answer 2

We have the same thing in German: Milchbubi, which is an insult for somebody who is immature for his age.

A baby which sucks milk from his mothers breast for a long time instead of eating real food is considered as backward for his age. This is then projected onto normal people by saying: You are such a milk baby!