Blood is our life force, yet it’s something that many people fear. This contradiction also creates pathways to arousal. “For some, it may be more about blood signaling a very intense experience, such as when blood appears from contact between a person’s fingernails and their partner’s back,” Lehmiller says. “For others, it may be a symbolic way of establishing dominance or submission, or something that co-occurs with sexual pain. Blood may also hold appeal to those who are drawn to the taboo.”