an emoticon to describe an eye-roll or to express something eye-roll worthy. The round parts of the 6 and the 9 are the eyes rolling around in one's head at the stupidity of the subject.
"She's only slept with him once, but she already knows they're going to get married. 6_9"
"Yeah, your arguments became invalid once I found out you were a Libertarian. 6_9"
A type of sex similar to 69. Except it there is a space in the 6 and the 9 because it is a type of sex where the 2 people smell eachothers genitals or farts from a distance. No joke. Some people actually like to do that.