He's got his left arm around her left shoulder. His left hand is resting on the back of her neck, and you can see that his left index finger is bent. The rest of his hand may or may not be sneaking underneath the neckline of her shirt. The bending of his finger creates a little box of shadow that may look like Jillian's hair. You're correct that there is a lock of her hair hanging down between her neck and his hand, but it's hanging DOWN and not spiraling out to the right where his finger is. Also, you can clearly see the slope of the top of her shoulder.
I can see where you're coming from but honestly, the video makes it crystal clear that it's his hand.