where the sun doesn't shine

1. In any location not reached by the rays of the sun. She wants to go spelunking for her birthday, but it gives me the willies thinking about clambering down into some cave where the sun doesn't shine. Deep-sea researchers have discovered several new species of fish in the darkest parts of the ocean where the sun doesn't shine.

2. vulgar slang In one's anal or vaginal cavity. The doctors want to stick a camera where the sun doesn't shine to check for cancerous polyps. I'm terrified of a tampon getting stuck where the sun doesn't shine, so I've always used pads instead.

3. vulgar slang Used figuratively by extension when one expresses their abject disdain, contempt, or disregard for someone or something. (Used especially in the phrase "stick/shove (something) where the sun doesn't shine.") Why don't you stick all that pretentious rubbish where the sun doesn't shine, eh? A: "How did you end up in jail?" B: "Well, the officer tried to give me a parking ticket, so I told him to shove it where the sun doesn't shine."