Frank J. Wilstach, comp. A Dictionary of Similes. 1916.

Supple

Supple as a young panther.
—Anonymous

Supple as the neck of a swan.
—Anonymous

Supple as tobacco pouches.
—Honoré de Balzac

Supple … as a young cat.
—Wilkie Collins

Supple as water.
—Victor Hugo

Supple as a snake.
—Guy de Maupassant

Supple as if they were on springs.
—Guy de Maupassant

Supple as the Scythian’s bow.
—George Meredith

Supple as a peau de Suède glove.
—Octave Mirbeau

Supple as Damascus steel.
—Ouida