A male displaying percieved feminine characteristics through actions which cause his peers to think less of him.Being a big girls blouse is much worse than being just a girls blouse, thus it's highly insulting nature.Also used to force a man to do something they fear through peer pressure.
Kate Winslet was explaining to David Letterman last week about the cold water they had to shoot in while doing "Titanic", and how Leonardo DiCaprio whined and moaned about the water being too cold. She called him "A big girl's blouse".