finish your business

Complete a dump

Johnny was playing with his phone in the bathroom. His girlfriend knocks on the door. "Hurry up, Johnny! Finish your business! I'm dying to go!"

Dying to go

Needing to go to the toilet right now, insomuch that it is a life or death situation

"Mum, are we there yet? I'm dying to go!"
"Not far honey. We should probably buy a Happy Meal or something so we don't get into trouble."