Actually Murder Machine is quite the good book, very informative and doesn't actually dwell into the many myths of the DeMeo crew. The blood ritual being one of them, Capeci never says in the book, in reference to Guglielmo that he performed blood rituals. Or maybe I must've missed that part. Coffey is a known to embellish details of his stories and out right make things up sometimes. Besides, he says Roy tasted some of the blood, some people taste their blood after a finger cut, that doesn't make them ritualistic blood suckers. And I wonder who could've told Coffey such a thing besides the only other rat in the crew whom is still alive, which is Dominick Montiglio, whom is also a known fabricator, his tale of the supposed Gambino meeting in which Paul Castellano was crowned official boss has also come under some scrutiny in recent years, as well.