Origin of sixty-nineFrom the resemblance of the figure 69 to the position assumed by the two people.
- (sexuality) A sex position where two people give each other oral sex at the same time.
(third-person singular simple present sixty-nines, present participle sixty-nining, simple past and past participle sixty-nined)
- To have sex in the sixty-nine position.
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.