used when sb says sth stupid or embarrassing and immediately wishes they had not said it
I, ETC. COULD HAVE BITTEN MY / HIS / HER TONGUE OUT / OFF
Meaning of I, ETC. COULD HAVE BITTEN MY / HIS / HER TONGUE OUT / OFF in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005