Open-Anus Fart 

When your fart opens your anus releasing a wad of air while producing no noise.This fart can either be stinky or have no smell at all. If your stomach hurts than your fart will be hot and smelly.

I just farted and it was open-anus. My stomach hurts..did you smell it?

Open-Anus Fart by steph and holly December 3, 2003

Open-Anus Fart 

While at the office, casually walk over to a co-worker as if you have important news. When their guard is down, drop trousers, and in one motion, spread your ass-cheeks as far as possible with your hands and bend over releasing pure gasseous matter directly into the unsuspecting victims face. AKA: OBH (open butthole fart)

I couldn't believe it when Josh open-anus farted right in the middle of the office. His ass was right in my face.

Open-Anus Fart by Ahmet K May 30, 2006

Open Anus Reverse Fart 

When you erect your anus towards the sky and open it with your fingers. Then you fart out and most likely your fart will be sucked back into your poop chute.

Mary walked up in front of the angry mob and performed and Open Anus Reverse Fart

Open Anus Reverse Fart by Elwoodthesheep October 26, 2010