What is "humping"

Usage examples of "humping".

Gregor shaded his eyes and stared along the white wake and across the dark waves, so much of it there was, until he saw a darker silhouette rise, humping out of the water about a mile away.

Lynn now, and each family had its herd of goats - the finest goats in Matabeleland, they boasted through sticky lips, and under the trees a homed old billy mounted a young nanny with a vigorous humping of his back.

He had dropped his head, and gone on, humping his back against the agony in his bowels, sustained by the rage within him.

There was a humping of the ground also, and even without sight Kethan knew that dwellers in the earth were tunneling ahead.