Simule

The act of trying to repeat a fart-like sound (such as scraping a chair leg on the ground, or the air escaping from a cushion as you sit on it) so that others around you know that it wasn't actually you flatulating. This very rarely works.

Everyone in the pews glared at Sue in church as she bobbed up and down on the plastic cushion in her attempts to produce a simule. They simply thought that she had farted and was now trying to disperse the smell.