I love the boyfriend line and this is a nice little addition for lounging around the house or tossing over yoga attire on the way to the studio.
I would size down. I got a small & definitely could have gone with xs. For reference I'm 34D size 4-6 hourglass figure 5'8. 140 lbs. Skims sizing is all over but if I purchased an xs I could wear it with just racer or bralet. Arm holes a little large. Definitely wouldn't wear w/o bra in small.
Rated 1 on a scale of minus 2 to 2, where minus 2 is Too Small, 0 is True to Size and 2 is Too Large