Medical and anatomical nomenclature is "perineal body."
The word perineum is a broad term used to describe a large area that includes the scrotum/vagina, anus and skin that lies around that general area. Taint is not perineum, but is the central point that lies in the middle of the perineum.
The history of: Pluto was actually located between Uranus (Latin for balloon knot) and Neptune (which is Latin for marble bag) and was originally called Taint. Plato (philosopher) likened this comparison to the area between a mans "marble bag" and his "balloon knot" and the planet became known as Pluto after the great philosopher. Taint (or Pluto as it later became) was moved to the other side of Neptune by Caesar who thought Plato was a dick.