where the sun doesn’t shine, phr. — Green’s Dictionary of Slang

where the sun doesn’t shine phr.

also where the skin turns pink

(US) a euph. for the anus, uus. in phr. stick it where the sun don’t shine.

1976		P. Conroy Great Santini (1977) 9: I’ve seen him take a drink or two to feed that wild hair that grows up there where the sun don’t shine. [Ibid.] 83: ‘Kiss me where the skin turns pink,’ Bull bellowed.
1989		R.G. Barratt ‘So Why Doesn’t Jack the Lad Get a Real Job?’ in What Do You Reckon (1997) [ebook] Others might [...] suggest I stick my typewriter where the sun don’t shine.
1992		B. Gifford Night People 179: You can stick the Egyptians where the sun don’t shine, far as I’m concerned.
2003		Guardian 28 Feb. 🌐 Hence we head into areas of prolific cursing, actual soiling of trousers (and on-camera inspection) and insertion of toy cars where the sun doesn’t shine.