Thi smay be caused by food piosining. It is part of the bile from the stomach, which is the mucus layer inside your stomach that stops the acid eating through the stomach wall. It may be advisable to visit your doctor, just to check if it is food poisoning or not?
I think you mean from the anus. This denotes an excess production of mucous in the bowel. It is a common symptom of inflammatory bowel disease. You should see a doctor if it continues or recurs.
If it is coming out of your vagina, that would be a yeast infection. If out of the urine tract, then it would be what booboo said. Definitely go see a doctor in that case.