I bought it. I’m still trying to get through it, but by god I’m going to read it.
Maybe I should leave it in the bathroom?
To also take the OP seriously, I have learned this trick (actually, learned is probably the wrong word, as it never seemed to take much effort) given that I have ulcerative colitis, and can feel an urge to take a dump for lengthy periods when circumstances prevent me from doing so. A sort of semi-conscious clenching is required to avoid accidents - that is, the clenching is of a voluntary (as opposed to autonomic) nature, but doesn’t require an actual mental attention. Unless the circumstances become rather dire, in which case finding a facility becomes mandatory regardless.