Originally, this was a dismissive nuclear reply to someone, suggesting that they leave you alone. Mainstream use has shortened the phrase from “Go lick
Jim’s asshole; he likes that” to simply Go lick
Jim’s asshole (GLJA) and expanded the meaning to include variations of non-compliance or disbelief - no way, dafuq, pound sand, kick rocks, GTFO,
STFU, etc.
While arguing with my sister, I asked if she wanted BK. She told me to go lick
Jim’s
asshole.
Bro, I just won the Powerball.
Dude, go lick
Jim’s asshole. You’re a fkn liar.