If you wanted to invent a phrase to convey the idea of boring, vanilla, hetero sex, you could hardly do better than "the missionary position."

It's a widely held belief that the name derives from 19th-century Christian missionaries in the Pacific Islands. Legend has it the natives mocked the churchmen for their teachings in the "proper" way to have sex as a Christian: with the man on top, and presumably in a manner that's joyless, quick and with minimal eye contact.

But it turns out the phrase was probably coined much later. It only appeared in print for the first time in 1948, with the publication of sex researcher Alfred Kinsey's groundbreaking book "Sexual Behavior in the Human Male," when he erroneously referenced a previous researcher's use of the term.

Regardless of the name's origin, the missionary position's association with a certain kind of bland sex has stuck over the years. Kinsey even referred to it at times as the Mama-Papa position—and everyone knows how hot it is to think about