Green’s Dictionary of Slang

porridge n.

1. imprisonment [the staple morning diet of such establishments in the UK + pun on stir n.1 (1)/SE stir].

[[UK]Leaves from Diary of Celebrated Burglar 79/2: The ‘molls’ had brought our bags [...] and placed them in charge of the old woman, with whom they lived while we were ‘doing’ our porritch and kail business in ‘stur’].
[UK]E. Stagg Night Scenes in London 90: ‘I ain’t as straight as some of yer, mebbe,’ he went on, ‘but I’ve ’ad me porridge an’ p’r’aps it’ll do me good.’.
[NZ]Truth (Wellington) 6 Apr. 6/1: List will avoid porridge till the end of his days.
[UK](con. 1920s) P. Beveridge Inside the C.I.D. 47: When the thieves were sentenced at the Old Bailey to long terms of imprisonment the case was neatly summarised by a tall City policeman [...] ‘Jam today, but porridge (prison) tomorrow’.
[[UK](con. 1920s) J. Sparks Burglar to the Nobility 72: Teddy [...] had blagged a relatively slight matter of five grand, but even so the Law felt he ought to go and eat some porridge for this].
[UK]B. Reckord Skyvers III v: I could still do what you expect me to be doin’, haulin’ Whitbread’s when I ain’t actually doin’ porridge.
[UK]Galton & Simpson ‘Live Now, P.A.Y.E. Later’ Steptoe and Son [TV script] Harold, I can’t do porridge at my time of life.
[UK]J. Sullivan ‘It Never Rains’ Only Fools and Horses [TV script] ’Alf hour later you’re doing porridge.
[UK]J. Cameron It Was An Accident 35: ‘I heard you were keepin’ company of police officers,’ he goes. ‘And you just out of the porridge. Got to be a connection there eh?’.
[UK]N. ‘Razor’ Smith Raiders 65: Maybe Ronnie could have gone through his whole life as a working robber and never got a tug from Old Bill or a long stretch of porridge.
[UK]K. Richards Life 228: Robert Fraser [...] had pleaded guilty to heroin possession. He had to do his porridge.

2. (Irish) based on SE porridge, a hotch potch.

(a) a confusion, e.g. a traffic jam.

[Ire]L. Doyle Dear Ducks 272: The two front mudguards an’ the other lamp were in porridge.
[Ire]RTÉ Radio news 12 Sept. In Wicklow something of a porridge took place yesterday in Fianna Fáil [BS].

(b) nonsense; usu. as you have your porridge, you are talking nonsense.

[Ire]‘Flann O’Brien’ At Swim-Two-Birds 167: It’s only a rabbit or a black tyke, said the Pooka. You have your porridge, said Shorty as he peered with his shading hand, there’s trousers on it.

In phrases

SE in slang uses

In compounds

porridge bird (n.) (S.Afr. gay)

1. a flaccid penis.

[SA]K. Cage Gayle 89/1: porridge bird n. 1. flaccid penis.

2. an impotent man.

[SA]K. Cage Gayle 89/1: porridge bird n. [...] 2. someone who cannot get or maintain an erection.
porridge stuffer (n.) (also porridge-stuffer) [stereotypical Scot. food]

(Aus. / N.Z.) a Scotsman.

[Aus]Bulletin (Sydney) 6 Jun. 12/2: The imaginative young porridge stuffer thought the donkeys were rabbits of a gigantic breed.
[NZ]N.Z. Truth 29 Apr. 1/8: [He] was informed by a porridge-biting friend that Scotsmen play the bagpipes as a hobby.

In phrases

stir the porridge (v.)

(orig. Aus.) to have sexual intercourse with a woman immediately after she has had sex with another man, esp. used of the final man in a gang rape.

[Aus]C. Bowles G’DAY 32: The bogs also have gang bangs in the backs of the bog wagons and the last one in stirs the porridge.
[NZ]McGill Dict. of Kiwi Sl. 108/1: stir the porridge one of the last turns in a gang rape.
[UK]Roger’s Profanisaurus in Viz 87 Dec. n.p.: stirring the porridge euph. To have sloppy seconds; to dip into a box of assorted creams (qv).
[NZ]McGill Reed Dict. of N.Z. Sl. [as cit. 1988].