Practice using the expression 뒷북치다

제가 제 1형 당뇨병 있는지 진짜 몰랐어요? 자주 뒷북치시네요..("뒷북치다" is not an expression that can be used to order people or people in higher position though..)

- You really didn't know that I have Type 1 Diabetes? You're always one step behind.

"넌 병원에 갔어?? 어머!" "누구나 벌써 알았어서 뒷북치지마." -

너 병원에 갔었어?? 사람들 다 벌써 알고 있는데.. 뒷북치지마

"You went to the hospital?? Omg!" "Everybody knew that already, quit making a fuss about it."

그게 안 들었어요? 누구나 알았어요. 뒷북치지말아요 -

못 들었어요? 사람들 다 알고 있어요. 이제 와서 뒷북치지 마세요. 

You didn't hear about it? Every body knows about it. Don't make a big deal out of it.