Bidet does not = to 马桶, isn't it? if that is what you mean?

The hotels I stayed that have bidets, they dont particularly provide a separate towel for that purpose.

BTW, top Japanese hotels all have bidets. Park Hyatt, for example, has bidet (with electronic control to boot). Park Hyatt is where the picture "Lost in Translation" was filmed - argubly THE most expensive hotel in Tokyo.