A person who has a strong physical thirst, need or craving for blood. Though this can be because of a sexual fetish, it's more likely to be related to physical or psychological problems (iron deficiency or the person believes they are Dracula).
"Goddamned sanguinarians...always bugging me for donations"
Someone in the vampire life style who has a physical thirst, need, craving for blood (which is non-erotic in nature) in more significant quantity than is generally required or desired by other blood-drinkers. Sanguinarians (a word from the Latin root "sanguinarius", meaning "bloodthirsty") apparently do not get the benefits from pranic energy, or else they are unable to feed psychically like psi and energy vampires, for whom blood and pranic energy are apparently interchangeable.
bill is a Sanguinariancan so he drinks blood insted of psy feeding
A person who drinks blood. Sanguinarians are not like hollywood vampires. They do not have rock hard skin. They drink blood cleanly, not by biting the neck. Sun does feel uncomfortable to them. But they will not burn up. Sanguinarians could be Christian or just about any religion. Not all of them are devil worshippers.
The donor met with the Sanguinarian so he could feed.