The expression "put tail between legs" means to show shame, defeat, or cowardice after a mistake or failure. Some synonyms for this phrase include shrink away, slink off, cower, skulk, sneak away, retreat, back down, and recoil. These terms all suggest a sense of retreat or withdrawal after experiencing a setback or loss. Other related phrases might include bury one's head in the sand, lick one's wounds, or hide one's face in shame. Whatever the exact phrasing used, these expressions all convey a sense of humility or embarrassment that comes from failure or mistakes.