You definitely don’t need two sizes up nor is it that tight. For reference I’m 5’4”, 200lbs and typically wear size 13 in FN jeans. I could’ve done my regular L or XL for room but to be safe (based on the reviews) I went up two sizes. It’s not that bad. But if you like your coverups to sit nicely, one size up is perfectly fine. There’s stretch with the waist. The thighs could be why you need a one size up