... THE ENCASED ELASTIC!!!
Lol I'm so happy with this little detail, I used to wear belts with this kind of dresses but the skirt would go up while I walked and the belted part would be super hot and rather uncomfortable in summer whereas my elastic keeps everything in place and it's like I'm not even feeling it's there :)
The fabric is quilting cotton given to me by my mama for Christmas, it's a much darker shade of purple in reality and I adore its irregular lines print. I put a slit and orange button at the back because I wanted to and that's that.