Holden is talking to the cab driver about ducks representing his inner innocence and childlike nature.
“You know those ducks in that lagoon right near Central Park South? That little lake? By any chance, do you happen to know where they go, the ducks, when it gets all frozen over? Do you happen to know, by any chance?”
The trouble was, I just didn’t want to do it. I felt more depressed than sexy, if you want to know the truth. She was depressing. Her green dress hanging in the closet and all. And besides, I don’t think I could ever do it with somebody that sits in a stupid movie all day long. I really don’t think I could.
Holden hired a prostitute and when she came she sat on his lap and still he still can not do it and finds her depressing. This scene represents Holden's unwillingness to grow and and his difficult relationship with sex and sex-related relationships.
Holden had been punched and had 5 dollars taken from him and this makes him more depressed. Holden is considering suicide and this scene is a repression of his loneliness and depression
What I really felt like, though, was committing suicide. I felt like jumping out the window. I probably would've done it, too, if I'd been sure somebody'd cover me up as soon as I landed. I didn't want a bunch of stupid rubbernecks looking at me when I was all gory.