When you shit in between a girls boobs (its got to be the sick wet, green diarrhea kind of shit) and then you tit fuck her. So you have the buns (her tits) the chile (the shit) and the hot dog (your dick).
When a female is in a doggy-style position, warms a hot dog in her vagina, places a hot dog bun at the exit of her vagina, then squeezes the hot dog into the bun while excreting diarrhea simultaneously, which creates the "chili" on the hot dog. Eating it or feeding it to another is optional, yet preferable.