A friend is writing a book about contemporary Taiwan that has a sociolinguistic component. She is writing on the expression 灑狗血, or making a scene, and she has heard that it is refers to a practice in Daoist exorcism in which the priest uses dog's blood when all other methods have failed. She asked me if I had any ideas, and, not being a specialist in either China or Daoism, I thought I would post here. Does anybody know if this explanation is correct? Also, if it is, can you point her to a good citation for it?
Thank you very much.