sometimes you just gotta let your hair down

Sometimes you just gotta let your hair down is a common idiom used to refer to behaving in a free and uninhibited manner. Someone who is letting their hair down is generally getting to a point where they are behaving without any inhibitions or worrying about other things in their life or what other people think about them. They are relaxing and enjoying things as they come, or being this way in regards to a specific situation.