"May I borrow your toilet?"
I read it in a book with Swenglish phrases (English phrases in a Swedish way).
That might be what a Swede say when he or she wants you use your bathroom.
No, we Swedes don't have any problem with mentioning the actual part of your bathroom that we want to use. We are not looking for a bath or a bed for a rest, we want to use the toilet.
And then the interesting word "borrow". In Sweden we borrow, though we don't intend to bring it with us home.
The funny thing is that we say borrow sometimes even if we don't intend to leave it back. Like my grandmother having a guest staying over night and the guest realizes that she forgot her toothbrush. My grandmother kindly said: "oh, you can borrow one of mine." An awkward silence filled the room until the guest, very uncomfortably, replied that she would prefer one of her own, unused.
Of course my grandmother was about to give her guest an unused to keep, not borrow.