It's when cuddling(facing the same direction, hence "22") with a significant other, partner, friend, or one-time acquaintance turns into kinky and ravenous sexual relations in the form of a "69".
Daniel: "Aww, dude last night with John went from 0 to 2269 real quick."
Kelsey: "Oh my gosh, sounds like a wild night. Heather and I have yet to make it to that level."