used to emphasize the degree of force of an action that you are describing

His dad would beat/knock/kick the shit out of him if he disobeyed. 如果他不听话，他爸爸就会把他打得屁滚尿流。

Don't sneak up on me like that - you scared the shit out of me. 别那么蹑手蹑脚地靠近我——你把我吓死了。