pack up your flaps - Telling someone to leave before you make their life a nightm

Telling someone to leave before you make their life a nightmare.

Your mom said, 'Pack up your flaps, or I'm gonna turn your room into a pigsty.'

Your teacher said, 'Pack up your flaps, or I'm gonna give you a pop quiz on the weekend.'

Your crush said, 'Pack up your flaps, or I'm gonna ask your ex to come back.'