The sandpaper worked back and forth against his chest.

His buttocks worked back and forth in the too-small bathing suit.

He worked back and forth among half a dozen radio channels, keeping track of as many conversations.

She stared at him for a moment, her upper lip working back and forth, then tousled his hair.

The rudder was still working back and forth; Fitzgerald knew the pilot had not given up.

They moved on up the slope, forced to work back and forth tediously in order to make the ascent.

They ground their teeth all the time; their jaws worked back and forth for hours on end.

The dog then begins working back and forth, starting near the hunter and slowly ranging out.

"Learning all seven dances benefits each of them; working back and forth between oil and acrylic has the same effect."

That's where the rivets have been working back and forth.