A variation of the 69 position. The practitioners lay down; head to toe; back to back. The participants then twist their backs around at the waist. Each of the participants' heads are now facing the butt of the opposite person. Oral to anal sex ensues.
Connor: Oh hey Nick, how was your weekend?
Nick: It was great, I totally pulled a twisty nine on this chick!
Connor: Woah dude you're flexible!