Taxi? Coat? What do those mean, exactly -- that if you make a mistake you have to leave?
The German ones are funny. At first I couldn't think of anything very similar in English, but then I thought of 'as the ... said to the ...' -- and lo and behold, the fruits of a web search.
Well, we all make mistakes, as the hedgehog said to the wire brush.
As the tree said to the lumberjack, I'm stumped.
As the pig said to the chicken regarding a ham and eggs breakfast, "You may be involved, but I'm committed."
As the deer said to the antelope, I think I just heard a discouraging word.
As the elephant said to the naked man, how do you eat with that?
You'd better gin a thought to yourself now. I got you into this scrape, and I mean to see you out, as the dog said to the 'possum in its hole.
I'm always on hand, as the cat said to the milk. (—Horatio Alger)
"Chonaic mé cheana thú," mar a dúirt an cat leis an bhainne bhruite. "I've seen you before," as the cat said to the boiling milk; once bitten, twice shy. (—BBC Irish proverbs page)
At least those are funny, if not familiar in the sense of widely used. You can turn up one or two on almost anything if you just guess a word and plug it into the phrase.
As the actress said to the bishop, ...
That one seems to be BE for pointing out a double entendre. No idea what the understood second half is.
As the artist said to the rock star, ...
As the refrigerator said to the hi-fi, ...
As the kettle said to the pot, ...
No idea about those either, sorry.