Stripping of Membranes?!?

I am 39 weeks 4 days pregnant with my first baby, I went to l&d last week and was 60% effaced, dilated 1.5cm, and -2 station. I lost my mucous plug today and my doctor is stripping my membranes tomorrow. Does it hurt to have your membranes stripped? What exactly does he do? and does it usually work within a certain period of time? Thank You