Let hair down.
放松
放下头发这个习语通常用来描述一个人放松自己，从严肃或正式的态度中解放出来，享受自由和休闲的时光。在社交场合，当一个人决定“放下头发”时，他们会更加自在，不再那么拘谨。
示例句子
Just let your hair down and enjoy the party!
放松下来，享受这个聚会吧
She's always so uptight; she really needs to let her hair down sometimes.
她总是那么紧张，她真的需要放松一下
At the team retreat, everyone was encouraged to let their hair down and bond with one another.
在团队休养期间，每个人都被鼓励放松并互相熟悉
