Wiktionary
n. (alternative form of crack-the-whip English) vb. (context figurative English) To make harsh demands in a position of leadership.
Wikipedia
Crack the Whip is a simple outdoor children's game that involves physical coordination, and is usually played in small groups, either on grass or ice. One player, chosen as the "head" of the whip, runs (or skates) around in random directions, with subsequent players holding on to the hand of the previous player. The entire "tail" of the whip moves in those directions, but with much more force toward the end of the tail. The longer the tail, the more the forces act on the last player, and the tighter they have to hold on.
As the game progresses, and more players fall off, some of those who were previously located near the end of the tail and have fallen off can "move up" and be in a more secure position by grabbing onto the tail as it is moving, provided they can get back on before some of the others do. There is no objective to this game other than the enjoyment of the experience.
The game is also illustrated in Winslow Homer's painting Snap the Whip of 1872.
Usage examples of "crack the whip".
Damian followed the movement, making it look like a very graceful game of crack the whip.
I think I'll need somebody on that line to crack the whip over them every so often.
Harn, the end player in a monstrous game of Crack the Whip, snapped into the cliff face and shattered like a crab dropped from a height.
But my mother was angry that Father should send someone to crack the whip over us, and Fiallach has not forgotten that you shamed him.
Now that youve got her on the job, I imagine youll crack the whip until you get what you want.