wazoo, n. — Green’s Dictionary of Slang

wazoo n.

1. the vagina.

1962		in E. Cray Erotic Muse (1992) 280: Let’s play hide the weenie up your old wazoo.
1974		J. Lahr Hot to Trot 20: One brick of Blue Bonnet margarine up her wazoo.

2. (US) the buttocks, the anus.

1972		B. Rodgers Queens’ Vernacular.
1988		Eble Campus Sl. Oct. 11: wazoo – rectum: That sucks up the wazoo that your dog died.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 185: The bozo who said sex is all in the head never had all of his dick up her wazoo.
2004		Mad mag. June 23: All this sand and seaweed up my wazoo.
2019		Twitter 22 June 🌐 And verily the Lord did decree ‘thou canst have spectacular jugs and wobblest on thy belly, or thou canst firm up thy buttocks and gut but lose thy wazzoos.

3. (N.Z. prison) the kit required for narcotics injections.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 201/1: wazoo n. a hypodermic syringe and needle.

In phrases

out the wazoo

(Irish) to excess.

2010

K. Barry ‘Fjord of Killary’ in New Yorker 24 Jan. 🌐 The estate agent had gussied up the history of the place in the brochure [...] heritage bleeding out the wazoo, etc.

up the wazoo

(orig. US) full up, as much as one can handle, to excess; all over the place.

1983		N. Proffitt Gardens of Stone (1985) 35: I got paperwork up the wazoo.
1992		J. Mowry Way Past Cool 8: We gonna be late an get tardies up the wazoo.
2001		C. McPherson Port Authority 8: Sitting on the toilet [...] Rocking back and forth. Staring into the fact that I’d blown it. Blown it all to hell up the wazoo.
2003		J. Ellroy ‘Stephanie’ in Destination: Morgue! (2004) 50: The tip got shined on. The tip got ignored [...] They had tips up the wazoo.
2015		S. King Finders Keepers (2016) 10: Critical bouquets up the wazoo, on the New York Times bestseller list for sixty-two weeks.
2021		J. Ellroy Widespread Panic 56: They left prints up the wazoo.
2021		‘Aidan Truhen’ Seven Demons 219: ‘I am Banjo Telemark Herr Eiger. I am connected up the wazoo’.