On the one hand, I love the idea, the catly abandon with which Catalina stretches, and the fact that Susan is completely herself, from her appearance to her being turned on by watching.
On the other hand, that tail is coming out the wrong place! The tail is a continuation of the spine; if it came out where it's pictured, Catalina's pelvis would have nothing to attach to! I know it can be hard to figure out how to combine clothing with tails, but completely breaking the anatomy just totally ruins any suspension of disbelief. Better to have it emerge from the shorts in the right place with no explanation, or give it its own little "leg", or have it emerge from one of the normal legs of the shorts, or anything else that's actually possible.