Get cracking
Definition 1 of 1
Pro Tip 1/3Informal Usage
The phrase 'get cracking' is informal and best used in casual conversations or informal settings. 
Hey, we're running late for the movie, let's get cracking!
Pro Tip 2/3Urgency Implied
'Get cracking' often implies there is an urgency or a need to hasten the beginning of an activity. 
The deadline is tomorrow, we really need to get cracking on this project!
Pro Tip 3/3Motivational Push
Use 'get cracking' to motivate others to start working immediately, especially if they're procrastinating. 
You've had enough rest now, let's get cracking on those chores.