Ok i am with Paul on this one...Now you have to explain that phrase...
Haha, do you mean to say you don't have that expression in the US, Janice and Paul?
Put simply, it's interchangeable with "Flat out like a lizard drinking," virtually meaning the same thing. In my previous example, "I'm flat out like a lizard drinking right now, mate. I'll catch ya later," another way of phrasing that would be to say, "I'm up to pussy's bow in paperwork right now, mate. I'll catch you later." Get a mental picture of a cat wearing a big bow under its chin, where a collar would normally be and you get the idea. It's another way of saying "up to my eyes," as in "I'm up to my eyes in work," or "I'm very busy."
It also has another meaning, as in "I've had it right up to pussy's bow with his nonsense. If he continues to annoy me, I shall give him a knuckle sandwich," meaning "If he doesn't quit annoying me, I'll punch his flamin' lights out."
I think I'd better quit while I'm ahead!
Feel free to plagiarize pussy's bow at will!!!