Thanks carbyville for looking into this. I know that the FNIT is a bit more lighted in the dvd than in the movie, so we can make more careful observations about this scene.
As you said, it is all wonderful choreography, no? Even unto the spittle and it's implied application. Ennis's hand moements are closely tied to this detail, and I thank you for looking into it closer.
The fluid motion starting from the application of spittle to the rapid insertion of the member is wonderfully done -- everything is implied, but by the movements, one can almost "see" the rapid progress of the attack. As I had said in the last post, a thread can be drawn between the use of spittle and moment of sexual hunger. It cross-refernences the senses in a strange but not all unexpected way.