sixty-nine /ˌsɪkstiˈnaɪn/noun 1number 1verb 1forms 4 noun1 •(slang) A sex position where two people perform oral sex on each other simultaneously. number1 •The cardinal number immediately following sixty-eight and preceding seventy. verb1 •(slang) To have sex in the sixty-nine position: to engage in mutual oral sex.You pat me on the head / You took me out to wine, dine, sixty-nine me / But didn't hear a damn word I said — 1995 formssixty-nined · sixty-nining · sixty-nines · sixty nines