Lets say you ate some cheese-puffs, or a (cooked) frozen pizza, or whatever... But when it come time to fart, it'd smelled like some other type of junk food you didn't even eat? It'd be like advertising via your own body.
*frrt* *sniff sniff* "Mmmm. Smells just like an open bag of potato chips."
As embarrassing as this is to say, this really happened.
Last x-mas my brother and I were at a bar shooting pool, and suddenly I smelled.....SOMETHING HORRIBLE.....and so did everyone else within twenty feet, and they just backed away......and the place was well ventilated. It was my brother. Fuck, I told him, that was like one of dad's. Like fresh cabbage sewage. Eww.