Sentence:  Suddenly a treble auto horn tootley-toot-tootled , and , <WSD>thumbing</WSD> hopefully , I saw emergent in windshield flash : red lips , streaming silk of blonde hair and - ah , trembling confusion of hope , apprehension , despair - the leering face of old Herry . 
Meaning of the word marked with <WSD> tags:  travel by getting free rides from motorists