Sentence:  We encourage their singing as much as we can," said the brother of the proprietor, himself a diligent <WSD>masticator</WSD> of the weed, who attended us, and politely explained to us the process of making plug tobacco; "we encourage it as much as we can, for the boys work better while singing. 
Meaning of the word marked with <WSD> tags:  Someone who masticates.