when people say they got stripped ..
I was just reading up on it because as a first time mommy-to-be I wasn't sure either! Looks like the dr uses his/her finger to separate the placenta from the inside of the cervix/bottom of the uterus in hopes of starting labor. If you google it you'll get all the info! I could be a bit off on some of the details - preggo brain!
There is a membrane that keeps the amniotc sac anchored and attached above the cervix, when this begins to break down the body is signaled to go into labor (that is why a fetal fibronectin test can tell you if you are likely to have pre-term labor or not), a doctor can help this along by using their finger to break the bond between amniotic sac membrane and cervix, it will bring on labor in some women, but not all.