During dinner? 
Hey, man, you’re the one who said it. And I’m not here to judge. Although you might want to tip the bathroom attendant a little extra once your done.
More genteel: “trouser cough”.
I think Mark Twain used the term “fundamental sigh”. Which is based on the euphemistic “fundament” = ass.
Less genteel: “Hey, did you fart in my pants?”
Saw a new one today. I know “handicapped” or “disabled” has euphemismed into “differently abled”, but here’s a Congresswoman (or Congressperson?) Euphemizing into “uniquely abled”.
We used to make fun of this stuff 35 or more years ago, in the non-profit where I was doing volunteer work around HIV/AIDS. My favorite satiric term was “differently othered.”
I’m sure it’s a tragic story and doesn’t deserve to be made fun of, but I notice one of the other MPSIMS threads listed at the bottom of this one refers to the murder of one “Ralph Yarl”. “Can you identify this badly decomposed body?” “Ralph! Yarl!”
“Uniquely abled” to me sounds like a child who can invert heir ears, or has their feet pointing backwards. Although I suppose in the latter case they would need special accommodations.
One from the UK that I was reminded of recently - maybe on its way out now, but “a guest of Her/His Majesty” = in prison
A Yank variant of that is “guest of the State”.
A long time ago in my high school, the phrase “I paid the Queen’s breakfast” meant you’d got a speeding ticket.
And “taking the Queen’s shilling” means joining the army. (Does it mean voluntarily enlisting, or getting drafted?)
Since, in the UK parliament, MPs are not allowed to lie, or to accuse another MP of lying, there are some ingenious euphenisms to get around the rule.
‘economical with the truth’, ‘inadvertently misleading Parliament’
One of my great-uncles spent some time in prison. There was a family story that he was “away at college”.
This was particularly amusing when I started college.
Sort of like the way a young unmarried woman would “visit relatives in the countryside”.
For nine months.
Voluntary enlistment. Legend has it that canny recruiting sergeants would make sure there was a shilling in the mug of beer they were offering an innocent yokel, so that they could say he’d ‘taken the shilling’ - and that’s why posh pewter mugs have a glass bottom (so that you see the shilling before it’s too late).
That reminds me that in Lea Ypi’s memoir of life in Communist Albania her family frequently refers to people’s time “at university”, and how long it took her to realise that meant imprisonment for various political faults
“Physics package” for “nuclear bomb” is an old one that came up recently.
When I was a teenager with a summer job, I worked with a guy who was living in a halfway house, before eventually getting to live on his own.
He always referred to his time incarcerated for drug dealing as being “away at camp”. If pressed, he’d say it was a state run camp.
Always a camp. Never a prison.