There's only one type of person in the world who would welcome seeing this on a t-shirt, and it's a doctor. We bet that doctors would find life much easier if everyone in their waiting room wore a t-shirt explaining their symptoms. It would make them all much easier to treat and prioritize. For anyone else, though, this shirt is just a case of too much information.
Given the design of the shirt, it's possible that this man works at a gas station, and is being forced to wear it by his employers. Maybe they haven't noticed the horrific double meaning that it suggests? If it's a genuine cry for help about an embarrassing bodily function, though, then all we can humbly suggest is that he drinks some peppermint tea and lets nature take its course. Also, is it us, or are the arrows pointing down totally unnecessary?