poo fumes
The lingering foul smell that follows a person who has recently evacuated their bowels. Often intensified in confined spaces e.g. on a transatlantic economy class flight.
"I say Reginald, that fellow appears to be dragging an odour around with him since visiting the toilet."
"Don't worry Edith, that's just his poo fumes."
"Don't worry Edith, that's just his poo fumes."