If you are actually able to do that you should be allowed to.
The hotel staff surely have a great sense of humor, great towel folding skills and a great deal of time on their hands.
I understand it's off limits for other people, but honestly I wouldn't want to be invited in such a place for a private event, no matter who's coming.
Let’s get together and enjoy our toilet time.
I assume there's an engineer living in this house.
For those unique and private moments, why not share them with a friend?
I need to go somewhere and make a call. I won't be too long.