Ah, yes the now-famous head-nuzzle. Bless you, Ennis...
To me, Ennis looks absolutely cocky, almost smug, doing this (I mean this in a good way. To me, he looks totally in charge, and on top of the world).
How many times in the movie do we get to see this side of Ennis?
Sad, when you think about it. He is usually so closed-off, introverted. And yet, in the right environment (i.e with Jack and away from prying eyes), there is joy, lust, and - heaven help us - FUN, within this island -of -a -man...