The mucus plug is a build up of secretions on the opening of the cervix that protect the uterus and baby from infection. Usually sometime in the ninth month you lose this mucus plug because the cervix is dilating. The mucus plug is a gooey substance that looks a little like gelatin. Sometimes you find it in your clothes, sometimes after wiping when using the bathroom. It kind of looks like a plug.
To be honest, this is the only pregnancy where I noticed that I lost the mucus plug. Quite often you can lose the mucus plug gradually and it seems more like a heavy discharge. Sometimes it has blood in it, sometimes it is clear.
The bad news is that it doesn't exactly mean that labor is hours away. You can have at least two more weeks to go!
It is strange that I looked up a lot of information on "mucus plug" but found it beneficial to read message boards on the topic and read what other women went through. Some said that theirs was clear, some said there was a bloody show, one lady said she wiped it up and showed it to her husband. (ewwwww!)
I don't have any weird stories to share, and this is the only time in my life that I will describe discharges. Pregnancy changes women, that is all I will say.