ShowPo Emerald Green Sequin Dress US size 6 (M) RUNS SMALL pls read description!

Floor length sequin dress from Show Po - worn once to a wedding! I am generally a size 4 - but had to size up to a 6, and it fit me perfectly. So the 6 runs small. I had the thigh slit closed up by about 3 inches so it wasn’t that high.