cotton wool

cotton wool
ˌcotton ˈwool noun [uncountable] British English
1. a soft mass of cotton that you use especially for cleaning and protecting wounds:
    She put some disinfectant on a piece of cotton wool and dabbed it on her cheek.
2. wrap somebody (up) in cotton wool to protect someone completely from the dangers, difficulties etc of life:
    You can’t wrap those kids in cotton wool all their lives.