have second thoughts

collect one's thoughts

To become mentally composed, especially after being distressed, surprised, or disoriented; to become calm or organized in one's emotional state or thinking, as in preparation for a conversation, speech, decision, etc.

just a second

A short period of time, typically anywhere from a few seconds to several minutes or more.

not leave one's thoughts

To remain in one's mind for a long duration.

penny for your thoughts

Used to inquire into the thoughts and feelings of another, especially when the person appears pensive or conflicted.

play second fiddle

To play a subsidiary or subordinate role to someone or something else.

second banana

A comedian who plays a secondary or supporting role, especially as straight man and traditionally in vaudeville or burlesque theatre.

second childhood

The period or state of cognitive decline of an elderly person, characterized by childlike judgment and behavior.

second fiddle

A sidekick or subordinate, or the role of such a person.