It is physically impossible for feces from the lower intestine to go back up the digestive tract to the mouth. The only way for feces to get to the mouth would be for a person to put it there. Expelling would be called "spitting out."
Feces.
Urine and feces are the wastes that are expelled from the human body.
The anus
Waste that is expelled from the body of a chicken. It's also called poop, feces, etc.
The feces of a horse is round when expelled due to the shape of the large intestine.
Meconium is feces expelled around the time of birth.
It is expelled as 'stool'. Stool is also known as feces.
the anus
The rectum collects the feces before it is expelled form the anus.
Excess water is removed from undigested food waste in the large intestine. This waste, called feces, is then stored in the rectum until expelled through the anus.
Anal canal or Anus
Feces are made in the colon/large intestine, then pass through the rectum and then the anus.