He smiled, taking her hand and kissing the back of it lightly. "This isn't the serum. I wouldn't risk bodies for it, especially yours. no, this is something else entirely. please, sit down." He gestured to the seat by the table, and he picked up the syringe, getting the bubbles out of it. He waited for her to get ready, then he was quick, injecting it into her vein in the arm with precision only a Vampire could do. "Ok, there. Don't flush it through the pores until later. I want to see the effects of it. now come with me..." He led her out of the room, through a tour of the basement, showing her the equipment.
What he had injected into her was a very powerful aphrodisiac. While she was a vampire, and able to flush it out through her pores, a normal human would have to sit with the effects for the full duration. The effect of it was the same, no matter the species. After about ten minutes, they would start feeling the heat, the hormones as he warmed up. The would feel the wetness around a half our after it entered their system. And a hour later, they would be begging for someone to take them to ease it. Only another person would be able to get rid of the intense hormonal heat that it brought on. Not even their hands, toys, or the surroundings would help, but make the heat burn brighter.