Follow the example of General Ripper:
"I first became aware of it, Mandrake, during the physical act of love. ... Yes a profound sense of fatigue, a feeling of emptiness followed. Luckily I was able to interpret these feelings correctly: loss of essence. ... I can assure you it has not recurred, Mandrake. Women ... women sense my power, and they seek the life essence. I do not avoid women, Mandrake, but I do deny them my essence."
Holy conspiracy Batman! I may not have any essence left!!