Answer: thumbing

AnswerCrossword Clue
thumbingTurn over (pages) with or as if with one's thumb
thumbingWear or soil (a book's pages) by repeated handling
thumbingRequest or obtain (a free ride in a passing vehicle) by signaling with one's thumb
thumbingTHUMB, to leaf through with the short, thick digit of the hand
thumbingPress, move, or touch (something) with one's thumb