A genuine dog and bone "dog and bone"

So my latest cockney rhyming slang entry brought up what I think is the first time I have seen the slang being made into what it is, dog & bone = phone.

I'll continue my search for a staircase made of apples and pears, someone married to a Teletubby, a hair piece made of syrup of fig or a watch that was really a kettle.

Dog & bone phones can actually be purchased on Ebay.
Labradors and golden retrievers seem to be the popular types.