Silent/quiet farts at the desk

After the first half of the day is gone, more and more people gather in the office and I am sitting at my desk, typing away and trying to read, concentrate on work and get things done, but it all seems impossible when I keep letting out all of these silent farts. They try to get louder, but I keep holding them in and making them as quiet and hissy as possible, so that no one will notice...but I'm not sure how much longer I will be able to do that for.