- tied\ to\ one's\ mother's\ apron\ strings
- Not independent of your mother; not able to do anything without asking your mother.
Even after he grew up he was still tied to his mother's apron strings.
Словарь американских идиом. — СПб., Изд-во "Лань". Оригинал: A.Маккей, М.Т.Боткер, Дж.И.Гейтс. 1997.