At one time I had a new employee who was originally from Denmark. She was a lovely person, but pretty coarse so I didn’t much watch my language around her, nor she with me.
Once in a while I’d something like, “That’s about as useful as tits on a boar hog.” Or, “You have to get everything you need from the customer before delivering everything on our side because they’re your best friend until they have what they want and after that they wouldn’t piss on you if you were on fire.” After saying some colloquial statement everyone else clearly understood, she’d ask me, “So why exactly would tits be useless on a boar hog, and what exactly is a boar hog?” I’d then have to explain that but for the protection provided by the sow or farmer separating the boar from the piglets, the boars have a tendency to eat the piglets so a boar would be unlikely to submit to being suckled by piglets, etc. It got to be an activity we both found amusing after a while. She works in a different department now, but still occasionally mentions she learned proper English in school and learned southern US red neck from me.