I was very excited.  I ordered the OSFM 14-22W [L-3X].  I am 5.8" tall and approx. 270 pounds (do not judge). But I had plenty of room in the dress when I wore it. Although you cannot see through the dress, I still recommend wearing a slip. I say this because the slip will keep the dress from riding into your backside.  Read between the lines. It serves as a buffer to keep everything smooth and free-flowing.