Sentence:  And so , after a flight southeast to Savannakhet , we found ourselves <WSD>bouncing</WSD> along in a Jeep right behind the Land-Rover of Prince Boun Oum of Champassak , a tall man of Churchillian mien in a bush jacket and a ten-gallon hat from Texas . 
Meaning of the word marked with <WSD> tags:  move up and down repeatedly