(flat) on one's ass
1.
mod. completely exhausted. (Usually objectionable.)
I'm just f lat on my ass. I need some rest.After the day of the marathon, Pete was f lat on his ass for a week.
2.
mod. broke; financially destroyed. (Usually objectionable. An elaboration of flat broke.)
Sorry, I can't help you. I'm broke--flat on my ass.The guy's f lat on his ass. Can you help him out with a loan?