有個對話，一個女生在廁所看到髮夾，跟男屋主借
請問其中的 knock yourself out 是什麼意思呢？
跟字典找到的都不太搭
Melodie: Who were yo talking to?
Andy: Myself.
Melodie: I thoguth I heard a woman's voice.
Andy: Yes, I'm very in touch with my feminine side.
Melodie: That explains the hair clip. Do you mind if I borrow it,
I left mine at home.
Andy: No, sure, knock yourself out.
電影字幕是翻成「當然，隨便用」