crawl into (one's) shell(redirected from crawl back into their shells)
crawl into (one's) shell
To retreat into one's mind or otherwise isolate oneself so as to avoid undesirable thoughts, situations, or interactions with people. After getting mugged, I crawled into my shell and didn't speak to anyone for nearly a week. I'm not good around large groups of people; I usually just crawl into my shell and wait until I can be alone. Don't crawl into your shell because you don't want an argument—talk to me and let's discuss the problem!