Having said that, the English form could hardly be more endearing, and it does communicate the basic idea of päntsdrunk, which is, yes, drinking alone at home in your pants.*
This means that there's no need for any layering of lovely, expensive, fluffy things; no outrageously expensive candles; and no simple snacks which take four hours to put together and no one really fancies in the end.
There's no need to be shiningly photogenic (they don't even have to be your best pants); no need to cover up the cheerful pineapple wallpaper with a stuffed moose head; no need to try to think of enough friends to invite who can be trusted not to spill beer on the white rug.
You don't have to buy anything (except your favourite drink); neither do you have to talk to anyone, or even switch off the telly. You can eat snacks from packets and check your phone (though not your work phone) whenever you like.
And all without having to wash your hair, run out to buy some new woollies, or smile.
You know something? I think Miska Rantanen, who's written a book to introduce the English-speaking peoples to this re-charging-of-mind-and-body concept (the book is called Päntsdrunk. The Finnish Art of Drinking Alone. At Home. In Your Underwear) might be going to prevent more nervous breakdowns than the inventor of the fluffy white rug...
...who, come to think about it, if anything, probably caused quite a few of them.
Lifestyle Trend To Try Today: päntsdrunk. This is the English form of the Finnish kalsarikänni. Kalsari means underpants and känni means drunk.
(Mind you, I've just checked kalsari känni on Google translate and got the answers, firstly, The fisherman tugged and then, on another attempt Shoe covers. So I'm not guaranteeing anything.)
*Pants in England are what some other countries call underpants.