the covering made of soft, smooth threads that surrounds and protects particular insects during the pupa stage as they develop into adult form

a safe, quiet place

the warm, safe cocoon of childhood 童年生活的温馨安逸、备受呵护

to protect someone or something from pain or an unpleasant situation

As a student you're cocooned against/from the real world. 作为一名学生，你处在与现实世界隔离的环境之中。