What to do about a needy dog?

There is a dog I look after regularly for about a week at a time (I'm a dog boarder) and it is so bloody needy... it follows you everywhere and jumps on your lap at any opportunity. It cries literally all night, not stopping at all. In walks it presses itself against my ankles. It is so annoying. The breed is an unusual looking yorkshire terrier... how can I help train this dog not to be such a frickin nuisance!