from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Vulgar Slang Oral-genital sex between two people at the same time.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The cardinal number following sixty-eight and preceding seventy.
- n. A sex position where two people give each other oral sex at the same time.
- v. To have sex in the sixty-nine position.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. being nine more than sixty
- n. oral sex practiced simultaneously by two people
From the resemblance of the figure 69 to the position assumed by the two people.(American Heritage® Dictionary of the English Language, Fourth Edition)
From the rotational symmetry of the numeral 69 – if rotated a half-turn (by 180°), the numeral remains the same, and a couple both giving oral sex at once have, in principle, a similar rotational symmetry. (Wiktionary)