I’ll use an example to describe how erections work. Companies advertise with air balloons that have air pumped into them. The air escapes but a fan keeps the pressure in the balloon high so that it stays full. If the fan is shut off, the balloon will collapse, or if there is a large hole in the balloon, the balloon collapses even if the fan continues full blast.

An erection works the same way. The penis fills with blood. The heart pumps faster and the two strictures (the corporal bodies) in the penis fill with blood. As they fill, they kink off the veins draining them so that the blood pressure in the penis rises. The blood keeps flowing but requires more pressure and the penis becomes erect with that pressure.

If the blood vessels in the corpora can not dilate and fill, the penis will not become erect. Medical therapy with either injections or Viagra will allow these vessels to dilate easily and the penis to fill with blood. Once this happens, the penis will be erect. Heart disease and hardening of the arteries, use of blood pressure medicines, some nerve medicines, and diabetes can all decrease erections by decreasing the ability of the penis to inflate. If the medicines or treatments used to help get erections get in the way of intercourse—penile implants need to be considered.

Remember that an erection is not the same as sensation. The sensation of touch and "sensitivity" of the penis changes with age and the diseases of aging. Medicine has no way to affect the nerves in the penis.

As a woman ages, her vagina may become drier and intercourse may be painful. If her partner is doing something for erections, she may wish to discuss better vaginal lubrication with her own doctor or her partner's doctor.

Intercourse is a two-party affair and works best with cooperation of both parties.