I can actually touch my chin to my elbow, barely, but not the way the characters were trying to do it.
you'll forgive me for having doubts unless there's dislocation involved..
Yeah, that's basically it. It's possible but hurts like a mother to do. Basically: extend your arm sideways so your elbow is under your chin, and rotate your arm so that the elbow meets your chin. I don't recommend trying it, though, especially if you don't have a lot of flexibility in your shoulders - I mean, I can hyperextend them pretty easily and it's still hard for me.