Quaking/shaking in your boots/shoes - Idioms by The Free Dictionary
quaking/shaking in your boots/shoes
quake in (one's) boots
To tremble with fear. Often used sarcastically. My brother is so strong and scary-looking that people quake in their boots when he threatens them. Ooh, I'm really scared of you! I'm quaking in my boots, you frighten me so!
(be) ˌquaking/ˌshaking in your ˈboots/ˈshoes be very worried or frightened: The prospect of facing the team again in the semi-final had everyone quaking in their boots.