knock (someone's) head together

Translations
образумить (кого-то), привести (кого-то) в чувство
The coach threatened to knock the players' heads together if they didn't start cooperating.
Тренер пригрозил образумить игроков, если они не начнут сотрудничать.
Definitions
To force two or more people to stop arguing or behaving foolishly, often by scolding or intervening firmly; to make people cooperate or come to an agreement, usually by applying pressure or authority.
Words
knock

verb
столкнуть
someone

pronoun
чей-то
head

noun
голова
together

adverb
вместе