The fluffy, furry and cute looking fabric is popular in this winter among young Japanese girls including my 8 years old daughter.
It is called 'moco moco'(fluffy in Japanese) fashion and it is available for pajamas, room shoes, leg warmers and socks, gloves, jumpers, etc. etc.
They are pretty affordable and as cheep as 105 yen for small accessories as above picture in '100 Yen Shop' like Daiso (http://www.daiso-sangyo.co.jp/english/).
Not only 'moco moco' makes your body warm but makes you cozy and feel happy as 'must-have-one-of-those' for this winter.