Damn that makes a hell of a mess. And covering your mouth with your hand just makes it worse.
Coughing isn’t much better, let me tell you what!
That’s nothing. Try throwing up while brushing your teeth - it happens to me all the time. I’d much rather sneeze.
The last time I sneezed brushing my teeth my lens popped out. Maybe it went into the toilet, maybe the sink, maybe on the floor, so I had to back out of the room carefully, one eye closed, dripping foam, to clean off in the kitchen before I could look for it. Eventually I found it stuck to the wall. 
Try sneezing while drinking a beverage and facing your best friend’s girlfriend. Nothing like covering his girl in Snapple to help keep things cool between you! Actually, later he told me that he almost burst a lung from trying not to laugh, but it was still pretty embarassing.
Sneezing while eating a bowl of Grape Nuts.
Those little buggers hurt when they get into your sinuses…
Oh dear lord that does hurt, and it makes the worst possible mess. Snot, milk, cereal chunks… Mmmm… all part of a balanced breakfast.
I’ve recycled many a bowl of Raisin Bran this way as a child. There’s hardly anything more disgusting, or more entertaining than blasting a wad of mucus, bran, and a raisin all over your sister.
Okay, I’m sorry. That’s just gross. 
Once when I was a kid, I was eating a bowl of Campbell’s Chicken Gumbo soup while sitting in front of the TV. I sneezed, and a small chunk of tomato went through my nose and onto the TV. Totally grossed my little brother out, let me tell you…