Good evening ladies and gents,
A comment in another topic reminded me of something from back when I was in college. As I was rather new to all this back then, I made a rather easy mistake. I wore a bra to bed and slept with it. Normally this wouldn't be a problem, but I had a red cross swimming class in the morning.
I didn't discover until after the class that my improperly sized bra had left marks on my torso with an uncanny resemblance to a certain female undergarment.
The moral(s) of the story is, if a bra leaves marks on you, it's probably too tight, and give time for the bra marks to disappear before going swimming when it does happen.