When conducting an old-school filibuster, the biggest concern of the person conducting it is that, sooner or later, they will have to go to the bathroom. To keep a filibuster going, you have to be on the floor at all times. Leave to go to the bathroom, and the filibuster is over; the opposition can swoop in and pass whatever bill you're trying to stop while you're in the bathroom.
Everybody, sooner or later, has to pee, and everybody, sooner or later, has to poop. Normally, this would limit how long a filibuster can truly go. But as at least one case showed, you can overcome this, at the low, low price of all your dignity.
In 2001, Missouri was in the process of redistricting, as per the 2000 census. One Irene Smith, a Democratic alderwoman in St. Louis, was upset with the proposed map, for the standard reason that her seat would have been put in danger. So on July 17, she filibustered. And she filibustered. And eventually her bladder started staging its own filibuster. After holding out as long as she could, and being informed that her filibuster would end if she left to go to the bathroom, she pretty much had to do something about it.
So her aides brought out a trash can, a tablecloth, a sheet and a quilt. Tablecloth, sheet and quilt surrounded Smith and trash can. No prizes for guessing what happened next. Although she denied it at the time, saying "What I did behind that tablecloth is my business." (Though she has since admitted to "alleviating" herself.)
For those who can't quite picture it, here's video of what an alderwoman peeing behind a tablecloth in the middle of July looks like:
On one hand, she won the day; the board of aldermen adjourned without a vote, and she was just kicking off a four-year term in her seat anyway (a seat she would leave in 2005 to launch the first of two unsuccessful campaigns for mayor). On the other hand, a month later, she was charged with public urination. The charge didn't stick, mainly because there was a tablecloth there and nobody could actually prove anything. (Apparently, nobody had the stomach to check the trash can.) And, of course, it's left a giant stain on Smith's political career that she still can't wipe away a decade later and she really wishes people would stop bringing it up.
Good luck with that, Irene.