have a field day
US /hæv ə fiːld deɪ/
UK /hæv ə fiːld deɪ/

1.
大做文章, 玩得痛快
to have an opportunity to do something enjoyable or to exploit a situation to one's advantage, often with negative connotations for others
:
•
The tabloids will have a field day with this scandal.
小报会借着这个丑闻大做文章。
•
When the teacher left the room, the students had a field day.
老师一离开教室,学生们就玩疯了。