Green’s Dictionary of Slang

high cotton n.

also tall cotton
[the wealth that comes from a high cotton crop]

[1940s+] (orig. US black) the good life, the materially successful life.

In phrases

shit in high cotton (v.) (also shit in tall cotton)

[1930s+] (US) to live prosperously, to feel happy, to be important; euph. alternatives include fly in high cotton, live in high cotton, travel in high cotton.