It's not funny! We recently sat through the movie "RV" which was erroneously listed as a "comedy". It should be listed in the evidence file for those making the case that Hollywood has run out of talent and Robin Williams should retire quickly.
Here is the thing: we all use the toilet, it is a well established, well documented fact of life. Watching Robin Williams get covered in feces is not funny, it is disgusting. It is also a sign of desperation on the part of whatever monkey wrote the "script". 5 year olds think potty jokes are funny but even they grow out of it! If that is the only thing you can come up with, please find another job.
Robin Williams is a genius as a stand up comedian, but it seems he has run out of ideas. There is something to be said for retiring while you are still on top before senility has fully taken ownership of your brain.
And while I am pointing fingers, Mike Meyers should also shut the door to the outhouse. It's not funny, it just stinks.