That means you take a sledgehammer and you hit right above the knee until you hear a sound, and that sound is like a rifle going off.

• 我这么说的时候，你就应该拿一个大锤子，然后向膝盖以上的部位猛砸，直到你听到一个声音，那声音听起来就像是一把来福枪在上子弹。