to go, retreat, etc. into your shell

idiomPart ofshell

to go, retreat, etc. into your shell — idiom

1. To become quieter and avoid social interaction, often due to feeling uncomfortab

1.idiom
Definition

To become quieter and avoid social interaction, often due to feeling uncomfortable.

Example

When criticized, Brian retreated into his shell for days.

Why does Sara go into her shell whenever strangers visit?