get your arse in gear
get (one's) arse in gear
rude slang To start being active or prepare to do something, particularly when one is inactive. I know you said you would take out the trash, but get your arse in gear and do it already! I really need to get my arse in gear and finish writing this paper—it's due tomorrow!
get your arse in gearBRITISH, INFORMAL, VERY RUDE or
get your ass in gearAMERICAN, INFORMAL, VERY RUDE
If you get your arse in gear, you make yourself start to do something, especially work. Note: The image in the following idioms is of driving a car. Of course Pat will be joining the project, if he ever gets his arse in gear. Note: You can also say that you get your arse into gear or get your ass into gear. You've got to get your arse into gear, girl. Nobody else is going to help you.