Kotowaza of the day: They don't wash those, you know

Japanese:

人の褌で相撲とる

Romanized:

Hito no fundoshi de sumo toru

Meaning of Japanese:

To sumo wrestle while wearing someone else's fundoshi (loincloth)

English equivalents:

Use someone as a cat's paw

Related:

To ride someone's coattails
To pull someone's chestnuts out of the fire
To rob Peter to pay Paul

The English equivalent and related expressions are the best I've found (or been given), but they don't come as close as I'd like to the sense of the original. Any other suggestions for sayings that involve taking advantage of another's position/possession to one's own benefit?