bring it on ＝ 给自己打气、壮胆、鼓舞士气
【例句】：
when the thief was arrested ,he wasn't nervous,he actually shouted at the policemen to bring it on.
小偷被捕的时候,他并不害怕,他甚至还冲着警察大声吼叫,给自己壮胆.