Prostate orgasm refers to a technique in which the prostate is massage or stimulated in order to produce a flow of seminal fluid from the prostate gland (males only)
The prostate gland is centrally located inside the pelvic region of the male; it sits below the bladder and immediately in front of the rectum, wrapping itself around the urethra in order to add to the flow during ejaculation. The area between the anus and the genital ‘zone’ is known as the perineum, which is in close contact with the prostate gland. So this little organ lend itself to hedonistic pleasure.
The main risk is that the sphincter (the ring of muscle that helps to control the passage of wind and faeces) may become rather lax over time. Make sure that you are relaxed, that your partner uses plenty of lubrication and you should practice safer sex precautions too, of course. Stronger condoms are recommended for anal sex. Do not put anything from the anus to vagina -- bacteria that live quite happily in the anus with cause havoc in the vagina.