have a field day

US /hæv ə fiːld deɪ/
UK /hæv ə fiːld deɪ/
"have a field day" picture
1.

大喜びする, 思う存分楽しむ

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.
タブロイド紙はこのスキャンダルで大喜びするだろう
When the teacher left the room, the students had a field day.
先生が部屋を出ると、生徒たちは大騒ぎした