The sound made by a man who died after willingly allowing himself to be anally penetrated by a horse. The video of this was posted online, but it was later revealed that the man had died from a ruptured colon. The expression is used as an inside joke between those aware of the video and also as a way to express a vulgar comment to someone incognito by just making the sound, when your really telling them to get fucked up the ass by a horse.
An instructor informs his students that the test scores for a recent exam are below satisfactory and that this is the worst class he's taught in so far. A student in the back of class makes the sound "Urgh ha huh!" and the class arupts in laughter. to the instructor's confusion he leaves the class having no idea what is going on.
by Savage3 July 2, 2008