The text is a smile because it's comparing someone or something being fierce to a fierce dog lapping its tongue using the word as. The writer is trying to emphasize that the person is very fierce and possibly aggressive as when a dog laps their tongue to drink water or lick their nose it's usually quick but rough.
This is a simile. By incorporating this technique, the author emphasizes the manner of ferocity and enhances the reader’s imaginative understanding of the text.
