Pretending to Be a Pig and Eating a Tiger

I'm Looking for a Book, I've Been Thinking About It for Two Days.

Looking for a book The female master initially got what a male disciple needed, but gave it to the person who helped her, and the male protagonist told the master. It seems that the master and his apprentice encountered a thunder monster on the flying boat, and then had to eat it. It is a book (not sure).