Definition
A stimulus or a wake-up call to motivate someone, typically to stop them from being lazy or unproductive.
鞭策，激勵
He needs a kick up the backside to start taking his studies seriously.
他需要一個激勵來開始認真對待他的學業。
Sometimes, you just need a kick up the arse to snap out of your lethargy.
有時候，你只需要一個激勵就能擺脫你的懶散。
The coach gave the team a kick up the backside, which made them play better in the second half.
教練給了球隊一個激勵，使他們在下半場打得更好。