I have posted several opinions here, of what I think the Jimbo scene is trying to say in the movie.
I can only interpret it as I see it in the flow of the movie and the story.
That Jack was buying Jimbo a drink to form a friendship, preferably sexual, and he was embarrassed and angry that he had such a public refusal.
That the bartender was making conversation only, when he mentioned "calf roping", so as to extinguish the situation and change the mood in the bar.
That Jack's angry reaction to the bartender, was more an angry reaction to his rebuttle by Jimbo, and the fact that he felt that he had been rejected once again.
And then the movie flows on to the following day when he sees Laureen, and she shows some interest in him, and then they meet in the bar, and this time the scene is completely different from the night before. The bartender has a different approach to him, because he asking about a female, and it is someone else doing the "flirting" or being the approacher to him.
I think Ang is showing the comparison between the atmospheres of how people react to a male/male flirtation and a male/female flirtation.
I also think that it is a realization to Jack, that he is gonna have to conform to what society accepts, by changing his lifestyle from one of being a gay male living in a society of rejection, to that of a man maried and settling down.
It is just another phase of the story, that shows how difficult it is for a gay man to live in that atmosphere, and when he makes a decision against his emotions to try to get some acceptance.
This is what the story and the movie are all about, this is what was happening in the story from the first scene to the last scene.
To insinuate that in the middle of this movie, Ang would add unnessary and perverted metaphorical conversation, which would only be recognised by people with likewise thoughts, is absurd...absolutely absurd.
