General euphemism for unspeakable yet socially acceptable acts of sodomy/mutual masturabation/heavy petting among consenting adults, usually of the same sex. Also British Slang for generally dodgy behaviour or misguided acts of affection. Never an insult, always with a raised eyebrow. Could also be a severe form of social embarrassment.
Stuart got promoted after some Jiminy Fiminy with Kevin.
Jiminy Fiminy is not Cricket.