I had my op at 3pm and they took it out late morning the next day.
Its a little bag - about the size of a money bag, on the end of about 1 foot of tube before is goes up your nose. You can feel it, but it doesn't hurt and isn't really uncomfortable but you are aware of it. The blue dye comes out your nose and collects in the bag, only something like a teaspoon full or two. You cannot smell or taste the dye. It looks more unpleasant than it is.
I was also really worried about the catheter but that was no problem either.