The phrase "putting one's tail between legs" typically refers to a person who is cowardly or ashamed of something they have done. There are many synonyms that can be used to convey a similar meaning, including "tucking one's tail," "shying away," "backing down," or "retreating." Other phrases that can be used to describe this kind of behavior include "fleeing the scene," "avoiding confrontation," or "ducking for cover." Whether used in a serious or lighthearted manner, these synonyms all convey a sense of someone who is unwilling or unable to face a difficult situation.