A virus, stomach bug, or illness that causes simultaneous vomiting and diarrhea.
Can create a quandary of which end of the body should be using the toilet: the head or the butt?
The combination creates one of the worst smells known to man.
Doctor: "What are your symptoms?"
Patient: "While I was vomiting I was also having diarrhea at the same time."
Doctor: "Ohhh..a double-ender. Sounds you like you have that nasty stomach bug thats going around."