As I understand it when this couple (a sexual chi eater in disguise and a human coworker) reach zenith he finds"a moment of perfect happiness" and is vulnerable to losing control. Then similar to when a magician depletes their own power source this could cause them (or a siphon) to lose consciousness, fall sick and even die. I think this is where her black out drunk type memory comes from. Maybe If they don't find the summit of bottomless bliss she won't drop to rock bottom so hard her memories get left behind. Maybe those sweet sweaty memories just get eaten all up... IDK Food for Thought