A gesture which indicates "yes, of course', commonly used in India. This gesture is where people move their head in a strange manner which looks like a sideways figure 8.
When I was in India, I asked people "yes" or "no" questions and when they meant to say "yes", they used a sideways figure 8 head nod to indicate that they meant yes.
Similar to the "69" sexual position, the Figure 8 (or Ate) occurs when the participants forgo the genitals and perform oral sex on each other's anuses. This move requires a further bending of the neck and a touching of the stomaches resulting in a figure 8 position of the bodies.
Friend 1: "Dude you got totally twisted last night!"
Friend 2: "Yeah man that butt was looking so right I had to taste it. She returned the favor too - we was all Figure 8."