For Short Kings in between sizes, size up.
"This feels warm to wear and smooth to skin. The design is pleasing. For me, the only downside is the sizing. I'm borderline 5'8" slim fit averaging 165. I had originally ordered Medium, but the groin area was snug or quite tight. It looked like it fits me in the mirror but felt like giving myself a wedgie I needed to adjust. I had to exchange it for a Large, which is just a little baggy, but it's more comfortable to wear, walk around with or slouch in. I can always add layers. Definitely the better size option for me. If you're like me, do yourself a favor and make sure you can raise your arm and sit well to know which one fits you better and provides more comfort for any onesie."