What if one is in a place on Shabbos where one needs to use the toilet and discovers that there are only rolls of toilet paper? By then not using the toilet could result in transgressing bal tishaktsu. Not using toilet paper would be contrary to kavod labriyos. What then should one do? Under such circumstances the poskim rule that one may tear the toilet paper using a shinui, such as unrolling a length of paper, pressing it on the wall with one’s two fists and then pulling the fists apart in order to tear the paper.  (see: Rav Dovid Ribiat, The 39 Melochos, volume 3, page 843) To avoid this situation, if one is living in area where there is an eruv, it is a good idea to carry a supply of toilet paper in one’s pocket.