Gumball isn't upset that the toilet paper is out. Gumball experiencing an existential crisis, as he considers an alternate universe where he is a cartoon character watched by thousands of people. People who are, quite possibly, watching him take a shit.
In this case, I meant "usual" in the sense that, when one takes a bath or a shower, they use their wash cloth to get in all of the nooks and crannies. In that sense that you may mean...that could make for an awkward part of the episode.