The poem sketches a awkward moment at a card game where the speaker feels trapped. The first lines suggest a social obligation: he is "forced to deal," as if he didn't choose to be there. Then the poem drifts into a blunt, uncomfortable thought about "the difference between a friend / and a whore." It's left unexplained, but it hints that the speaker is wondering what the people around him really want from him, and whether the company he keeps is genuine or only transactional.
Meanwhile, someone else seems lost in his own world, hearing "some symphony / of his own making." That image suggests a person absorbed in his private thoughts, or perhaps a self-satisfied companion who isn't paying attention to anyone. The speaker, by contrast, simply goes along: he will "perform my part / and part." The final pun, playing a role and then leaving, captures the mood well: detached, resigned, quietly bitter. Nothing dramatic happens, but the loneliness is clear.