Bunny Butt.

While Cardigans have a tail so the likening of their keisters to a bunny's is a little less convincing, I believe that you can still see the similarity. They also tend to 'bounce' when they run, strengthening this image.



I would also accept the descriptor 'Aladdin pants,' you know, the puffy kind of pants worn by the character in the Disney movie.

-Mel, Corgi-keeper