鬼拍後尾枕 (gwai2 paak3 hau6 mei5 zam2) — to let out a secret unknowingly in Cantonese
gwaiˊ²鬼paak˗₃拍hauˍ₆後meiˏ₅尾zamˊ²枕简 鬼拍后尾枕
Mandarin Pinyin: gui3 pai1 hou4 wei3 zhen3
Meaning of 鬼拍後尾枕
nounto let out a secret unknowingly
nounto reveal the truth without being asked;
nounA ghost slaps the back of one's head
nounto confess without being pressured;
nounslips of the tongue; Freudian slip (slang)