Understanding the phases of sexuality and how cancer can affect one or more of them can help you increase your satisfaction with sex.
• Desire  This varies from person to person, ranging from an uninterested, indifferent attitude to a very active
  desire for sex. Desire can often be increased by physical, visual or fantasy stimulation.
• Excitement  The body reacts to stimulation with increased blood flow in the sex organs and increased heart rate
  and blood pressure. Sexual interest and stimulation are characterized by an erection in men and increased
  vaginal lubrication in women, although a person may feel desire without those physiological responses.
      Sexual problems often occur during the excitement phase. This can lead to considerable anxiety and distress.
  Men may lose the ability to get or keep an erection. Women may not have enough vaginal lubrication for
  comfortable penetration, making intercourse difficult or painful.
• Orgasm  This is a peak of pleasurable expression followed by a gratifying relaxation. It is both a physical
  release and an emotional high.
      Some men might ejaculate only after prolonged stimulation. Sometimes nothing happens despite prolonged
  effort. Or the ejaculate might be reversed into the bladder (retrograde) rather than going forward and out the
  penis. The feeling of orgasm still occurs, but there is no semen or liquid.
      For women, the painful intercourse (dyspareunia) that sometimes follows cancer treatment can inhibit
  orgasm.