Semen (often mistakenly called "sperm") actually consists of about 65% prostatic fluid, the remaining liquid and sperm themselves coming from the testicles.
The mineral zinc is good for glands and is said to be especially good for the prostate, by supporting increased prostatic fluid production (prostate "flow"). Many herbalists also swear by saw palmetto, an extract made from a palm-like shrub that grows in coastal areas of South Carolina, to keep that flow moving nicely.
If the prostate feels a little swollen (often described as a "twinge insidesic my butt") its flow might be a little "backed up" and more sexual outlet is advised. The medical profession is much less likely to routinely screen for PSA's (an indicator of possible prostate cancer) than in the past because, in early 2010, the evidence indicated that so many false-positives had been generated that the cure (chemo, etc.) for the disease was worse statistically than the disease (prostate cancer) itself, on average.
Not to be confused with the word "prostrate," which means "stretched out face down on the ground in submission or adoration," or "to be lying flat."
"Will you have sex with me? It's essential to keep my prostate gland in good condition."
"So is masturbation. Get busy."