Blood donors
Blood donors are people that willingly allow human living vampires to drink their blood. Within vampire society, human vampires and donors are considered equal, yet donors are expected to be subservient to the vampires.
At the same time, donors are difficult to find, and because of that human vampires have no reason to abuse their donors. Getting even one donor is not always easy, even though there are people who willingly and happily offer themselves up for this role. Isolation and secrecy tend to make it difficult for many vampires to make contact with the people who would be willing to serve in this capacity.
Many of the big cities such as London, Paris, Milan, New York and Los Angeles have a well-developed vampire underground. In such cities, it is relatively easy to find the places where vampires and donors congregate.
Sanguinarians do not have long or sharp fangs. Some of them claim the reason for this is dilution via the prolonged interbreeding of vampires and humans. Others say the fangs are retracted when not in use.
However, sanguinarians rarely if ever actually bite their donors in order to draw blood. Biting is exceptionally risky as there are all manner of potent bacteria living within the human mouth. Bites can transmit the human immunodeficiency virus (HIV), as well as the hepatitis B virus and syphillis. Joint infections can lead to septic arthritis. Someone who has a human bite wound should get prompt first aid and see a doctor within 24 hours of the injury if the skin is broken.
In addition to the risk of infection, biting causes extensive bruising and other damage to the donor. Human teeth were simply not made to pierce flesh neatly and cleanly.
Fake fangs could technically be used to draw blood, but the vast majority of sanguinarians with a mind toward safety use sterilized lancets, syringes, razors or acupuncture needles.
Mutual exchange
Two people who are close will both gain from exchanging blood or energy. When an exchange of such nature is going on between two people it is preferable that they are both in a sexual frenzy.
In the case of two people exchanging energy, the two people will both gain from exchanging this energy. It seems that exchanging energy generally results in both parties feeling stronger, magickally, physically, and emotionally.