It could actually be one of two episodes.
'
1 - 'How to eat with your butt' - Season 5, Episode 10.
There were two people in it with faces like a rear end.
2 - 'Red Hot Catholic Love' - Season 6, Episode 8.
People put food up their backsides.
He is in the episode "fat butt & pancake head".
The episode Canada on Strike (episode 4, season 12).
The episode was Canada on strike and songs name is what what in the butt, This was episode 12-4 and he doesn't take it in the butt he just sings the "what what in the butt" song
Ginger Kids is episode 11 of South Park season 9.
"Scott Tenorman Must Die" (Season 5, Episode 1)http://en.wikipedia.org/wiki/Scott_Tenorman_Must_Die
canada on strike
He is in the episode "fat butt & pancake head".
"How to Eat With Your Butt" (Season 5 Episode 10)
The episode Canada on Strike (episode 4, season 12).
Tron Guy, Chocolate Rain, Sneezing panda, Giggling baby, Dramatic look prarie dog, Chris Crocker, what what in the butt
The episode was Canada on strike and songs name is what what in the butt, This was episode 12-4 and he doesn't take it in the butt he just sings the "what what in the butt" song
Ginger Kids is episode 11 of South Park season 9.
this is the south park movie
The South Park episode referencing Dubstep was Season 15 Episode 7 "You're Getting Old."
The second episode of South Park is called "Weight Gain 4000"
The 147th episode ever of South Park and the 8th episode of season 10.
"Scott Tenorman Must Die" (Season 5, Episode 1)http://en.wikipedia.org/wiki/Scott_Tenorman_Must_Die