Explain How It Is Possible For Person To Drink Liquid And Then Have Liquid Come Out Through The Nose When The Person Laughs?

I'm not exactly sure how, but your nose and mouth are both connected to the same tube somewhere while it's still in your skull which I think is the tube used for air to pass into your lungs ( esophagus ). If someone begins to laugh while having to liquid in their mouth the first reaction would be to swallow whatever was in their mouth. Since air is being pushed through your airway, through your esophagus ( if that's the right tube ), to escape through your nose/mouth and, at the same time, you're trying to swallow, the air going up your esophagus will push the 'liquid' up and, sometimes, it is pushed out your nose.
Well, that's just a laymen's ( however that's spelled ) opinion. I have by no means any experience in medicine, but it could be a close estimation.