Oh, I think this is a post of a home-shitter ( someone who only shits at home, not at someone else’s home, not in public toilets and definitively not in nature ) who tries to go on a multi-day hike. Rather a than getting over his mental block, he tries to prep his body to not shit for 3 days.

Poor soul.

when I was a child and was sent to summer camp, I refused to use the showers because they were communal

I probably would have tried to not use toilets too for similar reasons, but I had already had to learn to use public toilets because of public school