Given the track record of Matt Stone and Trey Parker's show South Park, it's no surprise that the MPAA changed their movie a lot -- but no one expected those changes to make the movie dirtier. According to Stone and Parker, every time the MPAA told them a scene was too raunchy for an R-rating, they'd submit what they thought was even worse, and, to their surprise, the more disgusting example was always given the green light.
via Letters of Note
"Cum-sucking ass"? Out. "Donkey-raping shiteater"? In!
For example, there's a scene in the movie where the kids discover a porn flick starring Cartman's mother. Originally the video was of a woman having sex with a horse, but after the MPAA shot it down, they resubmitted a longer version where she ate human feces. They meant it as a big fat "fuck you for trying to tell us what to do," but the censors thought it was fine.
The same thing supposedly happened with the title: The original name was South Park: All Hell Breaks Loose, but since movies aren't allowed to have "hell" in the title (a rule the MPAA has steadfastly defended forever without compromise), they resubmitted it as South Park: Bigger, Longer & Uncut -- which was accepted. The MPAA denies this, of course, because otherwise they'd have to admit that they let a boner joke slip past them unchanged, and we all know the MPAA never lets a boner slip by untouched.
That thing in the bed isn't a boner either. It's a toy.