Some lovers give their hearts. Blut Katzchen gives her blood.
Katzchen, 28, is a self-proclaimed "black swan," a person who willingly lets people who claim to be vampires suck her blood.
In fact, her name is the German term for "blood kittens."
Her current partner-in-plasma is Michael Vachmiel, 43, a Houston-based incense artist whom she met two years ago, according to Barcroft TV.
The pair began their corpuscle connection two years ago at a Vampire Ball in Houston, and have a few blood-sucking sessions a year.
Katzchen said: “You have to have a very strong connection to the person who is feeding off you," she told Barcroft. “Michael and I have a very intimate relationship and I trust him completely."
Still, the couple practices what might be called "safe sucks."
"I have specific tools that draw the blood and Michael will drink it from my body.The cuts are about an inch long -- it doesn’t take a very deep cut to draw the blood," Katzchen said, according to HuffPost UK.
Katzchen makes a cut with a razor blade and then draws out the blood from her shoulders or back with a set of suction cups.
Katzchen said she has been a "black swan" for nearly 13 years and has yet to contract an STD or other illness. What she does get is a feeling of satisfaction.
"It's a release like any other release people seek -- if you're getting something out of it and the drinker is too -- then I don't see a problem with it," she said, according to the Mirror. "It's a spiritual thing for me -- to be able to give energy to someone even if it's a small bit is an extremely liberation feeling."
Vachmiel has been drinking blood since the age of 13 and it is a way he gets energy and sexual satisfaction.
"Just like a person has a favorite culinary dish, vampires have a favorite spiritual culinary dish," he told Barcroft. "There are many ways to get energy, this is a more intimate way and it’s a ritual for vampires. In doing such, we get the energy we need and the donor has their need to submit, so it’s completely consensual."
Dr. John Mayer, a clinical psychologist who has studied the vampire subculture, has never met Katzchen nor Vachmiel, but said their comments in the Barcroft video suggest both are benefitting from the blood sucking.
"From a physiological perspective, blood has many nutrients in it that would give an individual a boost, so, from both a psychological/sexual and medical perspective [Vachmiel's] claim of the energy boost is probably accurate," Mayer told HuffPost Weird News.
Mayer, who has used his vampire research as the basis of a novel, said it looks like Katzchen is getting attention, sexual stimulation, identity, self-esteem and fantasy pleasure from her black swan activity.
"These are all things that she is probably not getting to this extent from any other source in her life. So, for her this is an effective coping mechanism for her life," he said.
D.J. Williams, director of social work at Idaho State University, recently published a paper about the challenges facing self-proclaimed vampires, a group he said has thousands of members around the globe.
It's a group he describes as people who are "successful," and "ordinary," but also very tired, hence their desire to find a consenting adult willing to give them access to their blood.
“Most vampires believe they were born that way; they don’t choose this,” Williams told Reuters.