I think you're almost right. Isn't it "Cowboys like U demandin beer after beer, smokin...it gets tiresome."
About Jack showing Ennis his hidden cigarette, does it mean that he's keeping his fire for Ennis hidden and protected? And is Ennis, by offering to share the cigarette, saying that his fire still burns for Jack, even after the mixup on the last day on the mountain?
I think this episode you point out, Mel, will have to go into the catalogue of favorite wordless moments, too!