Pronounced similarly to Diarrhea, the Skiarrhea is a move only few can pull off.
Whilst skiing with an upset stomach, one must start by "dropping trou". Keep in mind you would still be moving at this point. You then spread your skis apart and lower your ass cheeks close to the snow. Hover your ass cheeks close to the snow and let the shit fly. If done correctly, you should leave a nice brown streak on the ski run you are performing on.
Also keep in mind:
1) The Skiarrhea is even more fun if trou is dropped RIGHT in front of someone
2) The runnier the shit is, the more awesome the streak will be.
DUDE You totally left a fat Skiarrhea streak in front of that guy!
Damn dude what did you eat? You owned that guy with your Skiarrhea