( BrE ) to make fun of sb, especially by copying them or laughing at them for reasons they do not understand
TAKE THE PISS (OUT OF SB/STH)
Meaning of TAKE THE PISS (OUT OF SB/STH) in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005