sixty-nine
1. noun, vulgar slang A sexual position in which two partners perform oral sex on one another simultaneously. An allusion to the suggestive appearance of the numeral 69.
2. verb, vulgar slang To perform such a sexual act with another person.
sixty-nine
n. an act of mutual oral sex. (Based on the interlocking numerals in 69. Usually objectionable.) The old lady caught them in the bushes doing a sixty-nine.