That's kind of an English (British) expression that means something like "I didn't feel like doing it."
Ex: "Me mum asked me to walk the dog but I just couldn't be bothered."
"Couldn't be bothered."........ I'm still trying to figure that one out.
My Dad's phrases: "It's colder than a well digger's ass outside" and "I'm so tired, I couldn't pull a string out of a cat's ass" or if he was daring someone to do something, "you ain't got a hair on your ass if you don't".