Here is a nice definition: Meaning of cop it in English cop it UK informal to be punished or spoken to severely because you have done something wrong: You'll really cop it if your parents find out you've been stealing. You can check the full explanation here: https://dictionary.cambridge.org/dictionary/english/cop-it Hope this helps!

Richard is right. 'Cop it' is a very informal way of saying 'get into trouble'/ be punished.

Thank you! I see now. :)

it means, "they should agree with them or they will force them to.."