I'm back, a whole three days later! I really wanted to use some of the instances throughout the show when other characters ask if they slept together, and this seemed like the natural song to use for that theme.
This is my description box, so let me also add a little meta about little "All drama queens taking swings / all the jokers dressing up as kings" section in the middle: I am feral at the fact that both Sophie Lennon and Joel make being desirable and being funny mutually exclusive traits. Sophie tells her men don't want to laugh at her, they just want to sleep with her -- and then Joel doubles down on that thesis by telling her he can't be with her romantically if she's also doing comedy. So the fact that when Midge and Lenny finally sleep together the dialogue so explicitly addresses this cross-section of romantic/physical desire and comedy sends me to the moon.