Crack the whip
Definition 1 of 2
Pro Tip 1/3Assertive Tone
Using the phrase often implies strong authority and can be seen as dominating or forceful. 
The team leader decided to crack the whip during the meeting to ensure deadlines were met.
Pro Tip 2/3Not Literal
The phrase is metaphorical and doesn't involve an actual whip; it's about pushing for more effort. 
As the team lagged, the manager had to metaphorically crack the whip to boost productivity.
Pro Tip 3/3Potentially Negative
Be cautious, as it can be received negatively, like you're treating people harshly. 
When she started cracking the whip, some staff felt she was being too aggressive.