let one's back hair down

例句：

1. 1. After a long day at work, I like to let my back hair down and have a good laugh with my friends.
   工作了一整天后，我喜欢放松一下，和朋友开怀大笑。
2. 2. As the weather gets warmer, people tend to let their back hair down and enjoy outdoor activities.
   随着天气变暖，人们倾向于放松下来，享受户外活动。
3. 3. The boss was so stressed out that he couldn't let his back hair down and had to remain professional throughout the meeting.
   老板压力很大，以至于他无法放松下来，在整个会议过程中都保持专业态度。