What to do if you run out of toilet paper

First of all, don't call 911. Really. Some people have done that.
Secondly, take stock of what you do have.

Things you can use include:

Paper napkins
Facial tissue
Paper towels
Baby wipes
Adult wipes
Face wipes
Any other soft paper product you might have

Except - don't use cleaning wipes! And never, never flush these other paper products. Only real toilet paper should be flushed. We are having local problems because people are flushing other things down the toilet.

Put container with a lid near the stool and put used paper products in that. 

Now is the time to bring out those old t-shirts or rag material. You don't have to use them for your bum if you use them instead of paper napkins, facial tissue, etc. You can wash and reuse after using as a substitute for those things while you may not want to wash "toilet paper." (That's another post and if you do it, more power to you.)