They are not simply lustful looks but seem to suggest something more. That story, in fact, is announced and begun in the sex scene, with the looks exchanged between the two guys. The other is that it’s not an end unto itself but a set-up for the story that follows. One is that it is very artfully filmed and doesn’t include close-ups of genitals.
There are two things, though, that set it apart from most pornography. It should be noted that this scene is hardcore, meaning it contains erect penises and sex acts that are shown explicitly.