CC Cat Rainbow Doll House JSK in blue, size S. Not to be confused with the more common mint colourway. I wore it once to try it on, otherwise new with tags. Unfortunately I didn't feel like this dress suits me. 
Please keep in mind that I have both a cat and a dog, and while they don't come near my lolita and I will also carefully lint roll the dress before sending it out, I can't guarantee it will be 100% pet hair free.
According to the brand's measurements, the bust size for this size is 88-98cm (roughly 34-39 inches) and waist is 80-88cm (31-35 inches)