We had a Flight Surgeon at our Air Guard Unit that gave "medical" briefings at each Guard Weekend. On this particular day he said,
"Today's briefing is on the Sphincter." He proceeded to tell us that the sphincter is a muscle, which has no brain. But it has the unique ability to distinguish the differences among SOLID, LIQUID, and GAS. Unless you eat Thai food. In that case IT DOES NOT KNOW!
The moral of the story is: If you eat Thai food..... NEVER trust a FART!