The dutch one is better translated as “I’ll let it rust my crack” (as in buttcrack) rather than anus. It comes from the fact that we also used to use the word crack for “railtrack embedded in the pavement” as used by trams (streetcars). To let the crack oxidize is to not do proper upkeep on that section of the track. Though no one uses crack to refer to railway track anymore. So the translation is definitely the conn…
The saying is also used with comino (a cumin seed), pimiento (a pepper), rabano (a radish), all rather vegetarian, and culo (ass), and possibly other regional variants.
The "reet" in the Dutch expression of course also returns in "dat interesseert me geen ene reet".