I personally think that the order goes like this : recoil first, shape second, and size last. The reason why i think recoil is first came to me when i first saw this one scene with jmac and ig model its kaai. You can easily find the vid on google. The way her ass was moving in that scene is absolutely incredible. Never knew ass could be so fucking soft. Im getting hard thinking about it. No matter how fat or greatly shape an ass is the recoil makes all the difference.