Flatulence is the expulsion through the rectum of a mixture of gases that are byproducts of the digestive process of mammals and other animals. It is also referred to as a fart; the bodies natural potpourri; pinching the loaf and occasionally cutting the cheese.
Regardless of what you call it, depending on where you are when it occurs, who it happens to and the sound it makes will pretty much determine whether you will laugh or gag if it makes an appearance.
For example:
Just making a fart sound when someone is bending over can have a room laughing (it has to sound authentic). However, there is nothing funny about it if you are trapped in an elevator with someone who had a high a fiber lunch or in a steaming hot shower and one "gets away" - you might as well lock yourself in a garage with your car turned on because it engulfs you like an entity. There are times when you don't even know where it came from (unless of course it came from you).
How many times have you been on the train and someone lets one slip...all of a sudden everyone is looking around for an arrow pointing out the person who did it - guess what? That person is looking around also because they are not taking the blame.
In case you thought there was a point to this, well there isn't. It was just an "observation" made while in the shower. :(
