It's funny, I chose a ferret as my sona to reflect my lanky build in real life, but in the past couple years since I've been drawing Muffin, I've gotten a little bigger around the midsection and thought it only fair that he should share that aspect - plus it makes him cute and 200% softer!
And in canon, this may come as a bit of a surprise to most: none of it comes from bunnies! He's been very good! ...mostly good. He likes more snacks and junkfood than he should >.>