Among American adolescents, baseball metaphors for sex are often used as euphemisms for the degree of physical intimacy achieved in sexual encounters or relationships. In the metaphor, first prevalent in the aftermath of World War II, sexual activities are described as if they are actions in a game of baseball.
Among the most commonly used metaphors are the bases describing levels of physical intimacy (generally from a heterosexual perspective). Definitions vary, but the following are typical usages of the terms:
Additionally,
Additionally, there are two metaphors used to refer to men who have sex with men:
Other similar metaphors include:
The metaphors are found variously in popular American culture, with one well-known example in the Meat Loaf song "Paradise by the Dashboard Light", which describes a young couple "making out", with a voice-over commentary, by baseball announcer Phil Rizzuto, of a portion of a baseball game as a metaphor for the couple's activities. A similar example can be found in Billy Joel's song "Zanzibar" in which he compares himself to Pete Rose and sings the lines "Me, I'm trying just to get to second base and I'd steal it if she only gave the sign. She's gonna give the go ahead, the inning isn't over yet for me."
David Letterman chronicled many of these in his "Top Ten Baseball Euphemisms for Sex" — a recurring theme on the Top Ten Lists featured on the late-night talk shows he hosted before retiring in May, 2015.
Educators have found the baseball metaphor an effective instructional tool when providing sex education to middle school students. Leman and Bell, in their book A Chicken's Guide to Talking Turkey With Your Kids About Sex, make use of it to aid parents in the discussion of puberty with their children, dividing the topics into "first base" ("Changes from the neck up"), "second base" ("Changes from the neck to the waist"), "third base" ("Changes from the waist down"), and "home plate" ("The Big 'It'").