This fetish involves sexual arousal by blood. Yet, take note: "It can be super dangerous (for instance, consensual knife play as an extreme BDSM practice, which should be well-researched first and done only while sober and with a partner you trust 100 percent), but the sight of superrealistic fake blood around Halloween by way of bloody makeup and bloody crime scene decorations is a thing," she says.
Why?
Blood is life. It's powerful and primal, and many people get off on sexualising power and letting their primal desires come out.