Literal translation
he always has a fart running on him
Meaning
he's always got some small nagging worry
Explanation
Said, in mockery, of someone who always has some small health or mood complaint to report, nothing serious but enough to grumble about. In Provençal, the word family around pet (peto, petoulo, petoun) never carried the negative weight it has in standard French: it is used affectionately for a baby or a bit of cheese. Variants exist, a toujou l'uou for a woman, compared to a hen fussing as she broods, or a toujou un os que ié brando in the Rhône valley.