Was very loose, meaning it could slip off at any moment.

Donna's gym outfit wasn't originally hers, she'd traded it with a different girl who had went on a diet over a few weeks of vacation, leaving the outfit too big for her, which caused a problem of it slipping too much.

... Until Donna came to the rescue, she offered to exchange uniforms with the girl, since she was about the same size as her now (minus a few tight areas, Donna was VERY blessed), and it didn't escape this girl that if Donna was about the same size, she'd have the same issues as her, but then again, this WAS Donna.

Suffice to say, if there was a wardrobe malfunction today, it wouldn't have been the first time.