What does head down butt up mean?

"Head down, butt up" is an idiomatic expression often used to describe a focused and hardworking attitude, typically in a context where someone is fully engaged in a task or activity, such as studying or working. It conveys the idea of being so absorbed in one's work that the person is figuratively 'head down' in their efforts, with their 'butt up' indicating a readiness to tackle challenges. This phrase is often used in a lighthearted or humorous manner.