Hmm...I had 2 different things.
DD1 I had a grey coloured blood streaked stringy kinda loss, in 2 seperate parts. I was in labour that night, but it can be up to a week. At the time I thought that was the show.
DD2 I had very thick white mucous over about a week & I thought that was the plug.

But...when I had DS, I didn't see it, they said I was having my bloody show, so I'm guessing there was more blood?? I didn't have any cm or anything before labour with him though...no warning signs at all!