When you aren't sure what to do, think about his personality.. How would he pose?
If it helps, find a character on Google Image Search with a similar personality and see how they pose. It's construction paper, they don't do much in terms of overall movement. Make sure when you are posing to do BIG poses (don't have a dead arm, don't look stiff, ect.) Using the show for reference will only get you so far.
~Fellow South Park cosplayer ~