Lift Off Long Sleeve Jumpsuit

I ordered a M based on the measurements chart. I am 5' and 145 lbs., 38D and wear sz 29/8 pants in general. I typically wear a M but occasionally a S works better. I was torn as to which size to order but tried the M to start. Before returning the M, I ordered, received and tried the S. The S fits perfectly. Maybe the sizing is based on how roomy you want this jumpsuit? The S is neither "fitted" nor tight on me. It is perfectly comfortable. The M was just baggier or a bit too roomy (and less flattering IMO) for my preference. This is otherwise super cute. I'm not looking forward to using the ladies room in this jumpsuit, however. Taking it off and on is not difficult but it isn't the quickest, either. A thin tank underneath is a suggestion but their photo w/Converse is my new go to quick look. Adding a scarf or light jewelry gives it a little "class", but it's cute and sporty on it's own, too.