In only a little while he found different ways to make it sound by his manner of working the tongue.

A long, steady, even pull got that kind of a roar.

A short, quick one made it bark.

A pull half the length of the thong, a pause, and another pull, made it sound like a bark and a yelp.

To pull hard and quick, made it go louder, and soft and easy made it whine.