"have sex with" (v.); "the sex act" (n.), slang by c. 2000, perhaps a bouncier form of bonk in its popular venery sense. Related: Boinked; boinking.
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bonk v.
"to hit," 1931, probably of imitative origin; it is attested by 1975 in the sense of "have sexual intercourse with." Related: Bonked; bonking. As a noun from 1938; in the sexual sense by 1984.